My thought is simple aswell as level weapons and free fall sections why not make all boundries interactive. As far as i can remember corners and walls in mk were always boundries to trap opponants in, what does everybody think about abilities to use wall to your advantage, eg player 1 is backed against a wall and strategically presses say back and x and jumps against the wall and then launches at the opponant. The timing will depend on how far the opponent is if they're far away its easy the closer the get the harder the move is to time.
Using a ps3 as an example (< = back [] = square ^ = triangle) < and x could duck and sweep < [] jump back and throw a knockdown punch < O jump back then fly kick. < ^ could duck against wall and use a pop up < R1 could parry and swap positions and then u could couple a parry and attack together. this is a very basic version of the idea