I do realize that the reduction Sprint's proc-coefficient is a pretty cataclysmic change to what continues to endure as a very fun and diverse play-style that incorporates leap, rend, overpower, and war cry, among other skills. The reduction of the proc-coefficient means that many of you out there will no longer be able to farm without some form of upgrades that protects the player more so than sufficiently ignores the proc-coefficient.
That said, I have to reiterate that the build is still viable for the most geared of players. Other classes will no longer be able to point at the Whirlwind play-style and say it's easy to use. I spent a good chunk of my day teasing out different thresholds -- from lowering my critical hit chance to 38% with just one functional passive to utilizing a shield with my off-hand in my main-hand.
1) Attack speed is now the must-have requirement. I am not too sure of the lowest end one can go to make it work but on my gear, including the 15% dual wield bonus, I carry 47%. The higher the attack speed, the faster the tornadoes go, and the more likely you will proc. I believe this will be the singularly biggest change to the play-style. While one might say that Skorn users can continue to use the play-style, it would take an extremely geared player to do so.
2) Critical hit chance can go as low as 38% (based on gear) from my tests. With Overpower's Killing Spree rune and Wrath of the Berserker's 10% critical hit chance bonus, you can go as low as 58% without any fury management issues.
3) Fury dumping will be the toughest test of any player who thinks he's good at the Whirlwind. Knowing when to dump, how to dump, and how to use Overpower will be the biggest play-style check.
4) 24% move speed is another requirement. One could conceivably use 12% but the entire point of using 24% move-speed is to be able to stack with Sprint and Berserker. However, it's not necessarily to space out the tornadoes but to limit damage.
5) Crit Shields will be the next big trend once players have hit the raw 100k DPS threshold. Once gained, a well-geared player will equip a life-steal weapon and can gain critical hit chance in the following slots:
In total, a player can gain up to 55% critical hit chance and leave room to augment his passives for defensive ones, such as Nerves of Steel, Brawler, Tough as Nails, Superstition, Bloodthirst rather than using Weapons Master or Ruthless.
6) Infinite Wrath is very much viable. I made a point to show it today by spending 10 minutes holding it. I also did a quick test of the Alkaizer route to show that it is easy to sustain. See for yourself (starting at the 9:45 minute mark):
A lot more needs to be worked out (such as the breakpoint for attack speed as well as the low end one can use), but it's clear that few players will be able to farm MP10 with any ease. I have read a lot of posts suggesting that MP10 is easy -- I can say without question that it's not. It's boring, tedious, and unnecessarily protracted. I have checked out many of the specs of posters who have claimed to have had an easy go of MP10 and I am fairly certain that the majority, if not all of them, are lying about their proficiency. Even with over 1.1m EHP, I still took an inordinate amount of damage; I could not whirl inside a mob at any point without risking death -- every player who claimed to have had an easy go of MP10 had almost less than half my EHP.
Of some comfort, element damage is a lot more manageable in 1.0.5 -- it's the physical damage one will have to concern themselves over.
Ask me questions. I will answer.