I used to play a lot of tactical RPGs back in the day. (Vandal Hearts, Final Fantasy Tactics, Suikoden Tactics, Disgaea, Romance of the Three Kingdoms, etc...) Typically in a game like this you get to choose how your experience is distributed amongst your characters because whoever you take actions with gets the xp and the people you leave on the bench get nothing. Frequently you'll have a 'main character', often the one only plot relevant character you get to name. I develop an attachment to these characters which means I tend to use them more than the average character. This means they get more xp, which means they get more powerful than my average character. Which means when I get to harder fights I have to keep using them. The rest of my team is massively underleveled relative to the current content so if I want to win I have to bring in the big gun.
In Disgaea in particular I've tried to play the game with a balanced team. I've tried to level people equally but it never works out. I always end up with my favourite character taking more of the actions which means they're the only one who levels up with means they're the only one who can take the actions. I took to taking time out after every story act to level the rest of my team on the leveling map but the end result was still that when it came down to crunch time I still only used my favourite character.
In a single player tactical RPG that can even make sense. In Disgaea in particular for equal time spent leveling I can have a bunch of equal dudes or I can have one dude who blows them all out of the water. Even in a game with a more sensible leveling system the optimal play is still to power level one dude. With one caveat, which is that you can always bring that dude along on every fight...
In Romance of the Three Kingdoms (I only played part 3 but I assume the rest were similar) you were trying to conquer ancient China. You could take over one of the premade factions or could start your own in a neutral city. You could even play with other players as I remember my brother and I starting on opposite sides of the map and playing for days and never really interacting. At any rate, it took a turn to walk between two cities on the map, so once you owned a reasonable chunk of the map one army was no longer good enough. Stack your best dudes in one spot and you could beat anyone in your path but your opponents would take two cities from your backdoor for every one you took from their front. In order to actually win you needed to develop a few good armies rather than one awesome army. (Here you didn't really get xp so much as you provided them with more and better troops, but the theory still holds.)
So all your eggs in one basket is the 'best' way to play in Disgaea but an even distribution is the 'best' way to play in Romance of the Three Kingdoms. Something I've been trying to quantify recently is what's the 'best' way to go about playing in World of Warcraft?
What do I mean? World of Warcraft is a multiplayer game and barring multi-boxing you can only level one guy at a time anyway. Obviously you should put your effort into that character. But I'm not talking on the micro level of an individual character. I'm talking on a macro level of a raiding guild. Ignore that there are actual people behind these characters for now. Abstract that all away. You have a finite number of pieces just like in Disgaea or Romance of the Three Kingdoms. You have a finite amount of xp entering the system, though in this case it's purple loot and familiarity with encounter mechanics to be gained instead of a flat xp number or a number of archers. How should you set up your team to tackle 10 man raids? (My guild was a 10 man guild in Wrath and will be one again in Cata, so this is what I think about.)
Assuming no other constraints and that this is just a tactical RPG then clearly you just want to level up 10 dudes. Some fights want 3 healers and some only want 1 tank but mostly you want 2 tanks, 2 healers, and 6 DPSers. So I'd set my team up to have 2 tanks and split the tanking gear evenly between them. I'd have 2 healers of different gear types and split trinkets/weapons evenly between them. I'd have 6 DPSers of a variety of gear types and make one of them have a healer offspec. I'd want their mainspec to be a caster so they could reuse gear easily but give them a high priority on offspec stuff before any other DPSer. (Shadow priest would work, ret paladin would not.) I'd pick one of the two tanks to be the DPS guy and give him DPS gear over the other tank and both healers. I'd never change roles, so one tank is always the guy who is in the Abom and the other always tanks Putricide, for example.
This way I'd maximize encounter mechanic familiarity by reducing change. I'd maximize gear by reducing overlap and by splitting it as few ways as possible. (Likely I'd want one of my two tanks to be a feral druid to split tanking gear along type lines as well. And likely wouldn't want a rogue at all as a result.) In this way my little team would be ready for the hardest fights with as few trips through the power leveling map as possible. Just like in Disgaea, I don't want to spend more time on Cave of Trials, Stage 3 than I have to.
Clearly this wouldn't work in World of Warcraft without an insanely dedicated group. In a single player game your main tank doesn't go to Vegas for a week leaving the other 9 people picking their noses. Either you go to Vegas yourself and don't play the game at all or you stay home and have access to all 10 of your characters. There's no risk of a DPSer deciding he wants to play with other people and silently transfering to another server like a dork. Can we enhance our model here in some way to deal with these constraints?
Well, having to essentially start a new character from scratch to join with our powerful team is bad. If I can't reliably beat the hardest fights with my 10 pimped out dudes how can I possibly win with 9 pimps and a chump? If this is likely to happen then I want to have a contingency plan in place from the start. Grab an extra character of each type and rotate them all in equally. This certainly slows down my optimal path to killing the hardest stuff but makes so I don't just have to scoop when one of my characters permanently leaves.
Though honestly I'd have to ask if I'm playing the Manders RPG here. Why do my characters randomly leave in the middle of the game? I'd actually just level 10 guys and then stop playing for good when one left if I couldn't make progress with 9. Maybe I'd add an 11th guy and rotate around my DPSers (biggest pool of people so less watering down of the gear amongst them and increased chance the character death would hit this pool). But if I was playing Disgaea and was using Laharl exclusively and he up and left I'd turn the game off.
But wait, permanent death isn't the only option. In actual World of Warcraft people show up late. Or they miss an individual night with short notice. Maybe their internet went out. Maybe their computer gets so hot even frozen peas won't save it. Maybe they come down with the flu.
Which reminds me of the Bloodbowl league we ran at Chateau Monterrey back in University. I played the halfling race which only had two possible characters: halflings and treants. Halflings were arguably the worst units in the game. They had the least strength of any character. They had the least armor of any character. They had close to the lowest speed in the game and merely average agility. They had a couple special abilities that were quite useful and were incredibly cheap (good since they died so very easily) but they were not good. Treants were amazing. Second strongest unit in the game, the highest armor, and the worst movement and agility. Also useful special stats. But you could only have 2 of them on your team and they had a crippling drawback: a sixth of the time they just wouldn't show up. I had a bench to draw from, but the bench was more halflings. Frankly, any game where a tree sat out I couldn't win. It was a terrible feeling, and if I was taking it seriously I probably would have quit playing it as a result. (Well, and I could spent an awesome level up roll to remove the drawback. I got lucky (1 in 6 chance) and removed it from both trees pretty early on. It helped that trees earned a lot of xp for clubbing things.)
At any rate, back to World of Warcraft. I can't roll doubles and remove the chance of getting sick from any of my characters and I don't want to quit, so I need to come up with some other solution to the problem. The only solution seems to be to have a sufficiently large bench which have sufficient gear, skill, and experience levels to fill in when needed. Swapping in a halfling for a tree doesn't help but if I was allowed to have 5 trees on the roster but only 2 of the field at once that would be ok. Each tree would be worse so my odds of winning a specific championship game goes down (assume I need 2 high level trees to win) but my odds of winning any individual game - and of having fun - go up. The people earning world firsts in World of Warcraft have the commitment to go gung-ho with a super small dedicated roster but if I just want to have fun with my friends and kill everything a little slower then adding bench spots and splitting the gear and playtime around works ok.
One final problem though, which is that we have actual people behind these characters. They aren't just extensions of me with a random number generator deciding if they show up or not. In a single player game I'm happy as long as I get 10 dudes and a chance to win. In a multiplayer game I don't need to keep myself happy, I need to keep everyone happy. Everyone has their own motivations and their own restrictions on what will keep them happy.
Personally, I want to play the whole night when I start playing. Swapping in and out doesn't interest me (if I'm not in then I want to go do something else not hang around on the chance I might get in later). I want to play as many nights as possible, but committing to 100% attendance ends up making me unhappy. I'll get tickets to a hockey game, or get sick, or have a friend in town and just want to play Le Havre instead. I want to have the flexibility to be able to blow raiding off when convenient but also want it to always be there when I want to play. For the most part I always want to play so going with a 100% plan tends to be a good way to maximal happiness but when something else strikes and I can't take the time off the happiness plummets. (It's like I'm Adam's avatar from The Sims when he vistited Tom P's heart shaped house and watched Tom's avatar make out with Adam's virtual wife... I just want to sit at the bar and drink my low happiness bar away. If I drank, anyway.)
At any rate, if it came right down to it I'd almost be fine if raids didn't happen when I didn't show up and always had exactly 9 other people when I did show up. I would be if I was completely antisocial (I'm more avoidant than antisocial really) anyway. But I'm not and they wouldn't stick around if I was. So while I'm fine taking all the loot and practice and just screwing everyone else if I take off, well, it just can't happen that way. But what's the solution? If I was playing a single player game I might just accept that the guild shuts down if a tank quits but that's neither fair nor acceptable to the other people.
But what's the other option? I can see the argument for having 3 tanks and evenly rotate them in. A nice, even split of gear and practice. But that means only playing two of three nights. I didn't keep any stats from this last expansion but I've got a feeling I played a lot more than two of every three nights. I know back in TBC that Amaranthea and myself were in the 98% attendance range... Imagine 13 people with that attendance. Assuming their absences are independent (not true since days like Thanksgiving or Lounge Day will have linked absences). You'd always have 10 people for every raid which would be great, but you'd average sitting 2.74 attendees every raid. That's a little less than 80% actually getting to play when people show up. Is that good enough?
What about if people only show up 90% of the time? Well, then you need to cancel 3% of raids and you're down to sitting 1.74 attendees per non-cancelled raid. Better, but still not really good enough. And we're losing raids.
80%? Now we're losing a full quarter of the raids. We're only sitting .79 attendees per non-cancelled raid and everyone gets to play more than 90% of the time they show up.
What's the upshot here? Well, I think it's that you can't build a 10-man raid from 13 identical people. People either won't get to raid enough of the time that they show up or too many raids will get cancelled to not enough people showing up. You need some people with different expectations. People who don't mind showing up and not getting to play a good chunk of the time. You need diversity. Not just among classes, specs, and buffs, but amongst personalities.