I think what made MK:DA kinda rusty were the fixed combos. For example, on the moves list you could only use the combos they gave you instead of being innovative and letting you make up your own combinations of attacks. Do you think that a new combo system should be made for Deception???
It should be more loose and broken like the 2-D games were. Because of them being broken and loose, it led to some awesome juggle combos which were discovered one after another until the limits of the game finally kicked in.
With MKDA, the limits kicked in pretty quickly because of them making the game have combos set in stone and what not.