Ian the problem with the Digital Mortal Kombat images was that it limited moves and the uniqueness of the characters.
It was expensive to do costumes and have unique motion captured animation for many characters. So characters were mostly just color swaps, and even still almost every character had the same regular attacks. Same jump kick, same punches, sweeps and what not. It made the game bland, and the strategies no where near as deep as Street Fighter.
The Mortal Kombat 3D games may not have been much better, but at least the characters became more unique.