People took advantage of this.... situation
Instead of just aimlessly getting gear to get good damage and attack speed, people including myself would make the best of builds to just barely break that frame rate to make the attack or casting animation just one frame slower
you are at 80% increased attack speed and currently you attack at 6 frames animation speed
this is 6/25 of a second, so about 4 attacks per second
the next frame breakpoint is at 115%
This means that if you have gear that adds 34% attack speed, you will attack at EXACTLY the same speed as before
BUT if you have an extra 35% or higher you will go from 6 frame animation to 5 frame animation
5/25 is five attacks per second, a huge increase and all that mattered was that last 1% ias
This applies to cast rate and block rate as well
ANYWAYS, sorry about that long explaination
The point is, because we know that diablo III will obviously run at faster than 25, more like 60 frames per second, this circumstance that added so much end game content to the game, can not exist
UNLESS Blizzard somehow adds an invisible breakpoint system that creates small jumps in animation frame rates; which is my idea, perhaps at like 25% ias there is a jump in speed, and at 100% there is a jump, little goals to break for optimal agility
Sadly enough, this is probably one of the things that goes through my mind the most, I was thinking that you could do what you said, but never the bigger jumps at the breakpoints, I think it's quite the good idea though, I would be really disappointed if they kept DII's system.
I never actually tested this but I doubt its true.
The frame rate is only the rate at which the animation is DISPLAYED, and not necessarily the rate at which the action is calculated, nor the rate at which the server receives and interprets the action (affected by latency), thus although frame rate may affect how a spell APPEARS to behave it shouldn't affect how it actually behaves.
However, I don't think this would be easy to test either way.
Didn't the weapons for example have a speed in seconds and not like in D2 Fast Attack speed? Now when u get an item with 20% IAS that speed in seconds should go down by 20%.. I'm sure they rework this kind of things.
Since I'm a programmer, I've thought about this a lot.
There's a simple solution to this: Not have breakpoints - they aren't intuitive at all, especially to amateur players and it shouldn't be something you need to take your calculator our for. Since "frames" present a dilemma you just alternate between the next higher frame and the next lower frame from your current framerate and IAS. Say you are three fourths between 5 frames and 6 frames, the solution to this would be to attack 1 time at 5 frames and 3 times at 6 frames every 4 attacks - randomly.
You framerate will simply be the most your PC can render. Unless of course its locked at 60fps like UT3.
You can't do this because animations are locked at certain frames, most of the time about 30 FPS. Even if you're running at 500 FPS your animations are playing at ~30. In the case of Diablo 2 it was 25, but the most common numbers are 24 and 30 -> which are conventional animation timings in film. They might be as many as 60 in Diablo 3, who knows - but "breakpoints" will be a problem ( regardless ) unless you use a "stepping" algorithm like the one I suggested.