Let me give my half-rant:
I kinda expected this from all I heard, some inside stuff, some only rumors, so the only surprise for me was that this came out today and not at E3. MK or not, I was pretty excited when I clicked on the trailer.
This is NOT the way I want fighters to move forward. Midway tried to add gimmicks in all their games mk4 until now, and it didn't work out before. I believe it should stay as only the characters themselves providing the tools for combat. What should change is the uniqueness, balancing all the characters while making each fighter original with unique strengths and weaknesses. In a way, I'm optimistic about the way Boon described the characters. However, the stage thing REALLY irks me.
Right now, we have tons of complaining about stages. Rooftop vs The Pit is annoying enough, but now we're going to have all this environmental impact? I don't understand how you can make a competitive game this way unless it's absolutely perfect. They haven't done anything to progress this yet, so why should we expect it to work out so well this time? If mk9 was basically an mk10 beta, Injustice might be the same way. I thought NRS learned from their past mistakes. Will it be a fun game? Probably, it's just a matter of how it will work in high-level play.
However, we only have limited material right now, so we can't go too far with our judgments. I'll keep my hopes up for sure. Things will certainly alter in the development of this game, so we'll have to wait and see.