The Sentinel nerf doesn't surprise me in the least.
An example of a perfectly good strategy for destroying Sentinel. Most with skill would've discovered this video or their own strategy how to beat him; the driving force behind the nerf was (to be blunt), for noob players, for a noob game. Not to say it isn't enjoyable, it really is to me, but this is certainly up there for most accessible 2D fighter I've ever seen, and I'd say most accessing it aren't there to become masters or experts in the game. After Sent, I wonder who's next to be sent to the nerfing block.