First thing to mention is Sceadeau found a pretty great blog post with a lot of details about the combat mechanics in Diablo III. It looks to be mostly based on beta information and is wrong in at least one place (vitality is worth 35 health at level 60, not 10) but it seems pretty reasonable overall. It certainly helped explain some of the things I found out yesterday with how often beams tick and whatnot.
I ran some more tests last night. Blizzard and meteor both do substantially more damage with the slower weapon than the fast one. Even when I put on my damage ring the faster weapon wasn't making up ground in terms on blizzard damage. With beam weapons the faster weapon at least made better use of bonus damage. With blizzard it's just flat wrong to use a fast weapon. Less damage per arcane power. Less damage per second. Maybe you become able to walk sooner after casting? I don't know, and it doesn't really matter.
I need to test the signature spells at some point. I have a feeling if a faster weapon is ever going to show returns it's going to be with the signature spells. Especially if you spend runes/passives causing them to restore arcane power? My feeling while leveling up was they didn't do enough damage to be relevant but maybe that was just perception.
One important thing to come from learning about the .5s 'cycle' for beam weapons is realizing that I'm doing more damage than I thought I was. I would see a 10k number on a beam and think I was doing 13k DPS with a 1.3 speed weapon. In reality I was doing 20k. Last night I bought a good weapon (1.2 speed now along with 150 more base DPS) and had good shoulders and a fantastic set ring drop which raised my beam damage up closer to 20k per tick. Knowing that if the monsters aren't hitting me I can sustain close to 40k DPS on a single target at range for a reasonably long time makes me feel a little less useless. It's still a far cry from Sky's 100k number but it's at least playable. Probably in the 26-30k DPS range to a pack of dudes with the piercing beam. I can beat most elite packs in inferno Act 1 by myself now and am probably a useful inclusion in a group. I switched to using blizzard even though it does mediocre damage in order to kite things more efficiently with the huge area slow. Running a vortex dude in circles around a clump of trees is pretty hilarious.
In case anyone cares, raw damage numbers from the tests after the break...
mace chaos nexus- 1183 damage, 21 ticks, 118.3DPS
dagger chaos nexus - 558 damage, 11 ticks, 111.6DPS
mace meteor - 499 damage
dagger meteor - 151 damage
mace - 369 damage
dagger - 218 damage
mace - 360 damage
dagger - 157 damage
mace blizzard - 300 damage
dagger - 173 damage
mace - 288 damage
dagger - 185 damage
mace w/ ring - 521 damage
dagger w/ ring - 380 damage
mace - 543 damage
dagger - 398 damage