All that stuff is good in theory, but when a 'variation' of Robin has a hitbox half the original size like the Damien 'variation' would be then what's really the point of them not being seperate characters.
The concept of bringing variations or character-alternates to Injustice falls apart anyways when you try to project the idea past a few key characters. Gadgets Batman, Takedown Batman, Kung-Fu Batman sounds good, but try doing that for Aquaman or Superman. (Freeze Breath Superman, Heat Ray Superman, Superbreath Superman?)
Hal, John, and Guy! ....But Cyborg, ummm Victor, and umm Cyborg