If I read "this game is boring because the combos suck" one more time, I'm going to strangle a rabbit.
The reason this game sucks has nothing to do with combo variation. I hate how people judge other people based on the combos that they do too (Dat infamous "seriously? that's the only combo you know with him? I know 4 or 5 with him so I'm better" argument).
The goal of a fighting game is to be the first player to deal 100% (or 200% in Injustice's case) damage to your opponent. Combos are just a way to deal that damage. Who is the better player? The one that wins landing the same 20% damage combo 5 times, or the one who has a 20%, a 25%, a 35%, and a 41% combo but he loses because he can't set them up? OBVIOUSLY the latter one right?
Who f***ing cares about combo variation? High level fighting game play (excluding Injustice) is fun to watch because it's like a good boxing match. There is a ton of little pokes, movements, and projectile checks with the goal of trying open the other guy and capitalize with some big damage (unless it's Injustice where it's pretty much "hey, this move is safe, so I'm just going to throw this out there an see if he unblocks").
The same combos are done by everyone in ANY fighting game, it's just Injustice is boring to watch to begin with, so it's harder to tolerate
COME. AT. ME. BRO.