The main problem with pure Henshin vs Acrobat is that Acrobat gets +15% attack speed right off the bat while Henshin has to wait until level 20. Add in sneak attacks + Improved Feint and Acrobat out-DPSs Henshin in lower levels. Henshin kinda-sorta made up for that later on with a ton of Melee Power in the cores...until SSG decided that the best way to nerf overperforming Shintao builds was to rob Henshin of all that MP.
So pure Henshin went from 80 MP down to 35.
It's nice when Void Strike's instakill procs, but since it's a vorpal effect with a 3-second CD, the net effect is one free kill every minute. Where Henshin distinguishes itself IMO is the added utility of monk abilities: Shadow Veil, Balance in Dawn, etc. Whether that's worth giving up the added DPS from pure Acrobat is up to you. Or you can split the difference with one of those rogue 12 / monk 6 splits.
Falconry+Henshin opens some synergies since Henshin DCs are WIS-based, of course, but I'm still left with the feeling that (despite the nerfs) Shintao is still so much better than Henshin that it renders stick builds moot (again).