What do you think about something like this for Windwalker?
(Concentrated Chi): Jab is replaced with a passive ability called Concentrate. You no longer passively lose Chi. Your Chi refills with refill speed based on number of Concentrate stacks. Each time you spend Chi, gain one stack of Concentrate per Chi spent. Each time you gain one Chi, lose one stack of Concentrate. After 4 seconds at maximum Chi, Concentrate stacks will begin to fall off.
(Proper Concentration): You have a chance equal to your mastery to gain one additional Concentrate when using Chi. (Percentages over 100% may trigger additional times.)
At that point, your Chi abilities are basically just using Energy and Energy becomes useless (which it kind of already is). Energy regeneration then also becomes enhanced with Mastery, and it creates a pretty strong vers/mast burst synergy. (Instead of the haste AA progression designed for sustained throughput.)
At the same time, high mastery will see a really fast paced burn (and a little struggle with Combo Mastery twisting) when the fight ramps into Concentrate windows. I worry this may OVERSHOOT though, with Haste/Mastery absolutely dominating weights. For AoE instead of ST though, Mastery would absolutely crush.