Credit to chthonvii over at
https://www.reddit.com/r/Diablo/comments/t3yfmu/new_ptr_druid_ias_cap/This is his post:
I don't think we have enough information to really say how these changes are going to shake out. I'll do my best to summarize what we do and don't know:
They're going back to the original PTR change. That means using the standard IAS equation with manform's ass-slow base animation speed (instead of the longstanding special wereform IAS calculations). Taken alone, this is a nerf to everything except some very slow base weapons that weren't viable before, and still aren't viable now.
They've also increased the EIAS cap. This deserves some explanation, since many people probably don't know what that is. The standard IAS equation works like this: First convert IAS on items to EIAS via a diminishing returns formula; Second take 100 + EIAS + skillIAS - base_weapon_speed (recall that faster weapons have negative speeds, and subtracting a negative yields a positive); And third, cap the result at 175 (which is 100% of base animation speed plus up to a 75% bonus). So that +75 cap is changing to +150 while in wereform.
So this raises two big questions: First, is the increased cap high enough that the old speeds of 4 or 5 FPA can be reached at all, given the awful base speed? Second, is it going to be realistically possible to obtain enough IAS to reach them?
As to the first question, it looks like the answer is probably yes. Warren1001 wrote a calculator for the first PTR that appeared to be correct at least as to the basic attack. If we take that and change the EIAS cap to +150, then it looks like the maximum breakpoints are faster than at present.
The big question marks are Fury and Feral Rage. Warren1001 couldn't figure out what Blizz had done to the IAS calculations for these skills in the first PTR, and, so far as I know, no one else did either. My guess is that these skills also have a faster maximum breakpoint in PTR2 than present, but I'm not as confident about that as I am for the normal attack.
I don't have the faintest clue what "increased speed between attacks by 40%" means. I'm guessing they've either changed the base speed for the first 4 hits or maybe you get extra IAS while using the skill? The wording is really clear as mud.
So how realistic is reaching the maximum breakpoints going to be? For werewolves, probably pretty easy. But it sounds like werebears may be kinda f--ked.
Presently, given a fast base weapon speed and realistic skill levels, the IAS from Werewolf alone is enough to significantly exceed the +75 cap, rendering moot the IAS bonus from further ranks of Werewolf and all IAS from other sources. So the increased cap means that you get your full bonus from Werewolf and gear IAS becomes relevant. Plugging current popular weapons into the modified calculator, it looks like breakpoints at least as fast as current speeds are reachable with Highlord's and/or 20% IAS gloves on top of the weapon IAS. (Though, again, not being able to run the numbers for Fury leaves a big question mark hanging.)
On the other hand, it looks like werebears are in a bad spot. They're saddled with the new formula and awful base animation speed, but it's not as easy for them to get enough IAS that they benefit from the increased EIAS cap. Clearly, Blizz intends us to use Maul as a "poor man's Werewolf." The notes say 3 IAS per charge, and Maul has slvl/2 + 3 max charges, so you might get 50ish IAS out of it. But you have to charge it up from zero and then keep it going. That's going to be inconvenient for Fire Claws builds and impossible for pala-bears and bear-sorcs. And even then I'm not sure you'd be getting back to 4 frames. I suspect this is going to wind up being a straight nerf to at least a large share of existing werebear builds.