I felt injustice was a good game, and served as a litmus test for mechanics for MKX as well as establishing a new franchise which, sales wise, was a success.
I think for many initially it was too much of a drastic change from mk9, so I can't blame players for not liking it. We went from one game, which has fast walk speed, dash-canceling, a block-botton, similar jump-in attacks, good anti-airs, and overall good poking tools to another, which had large hitbox jump-in attacks (and also variable jump in attacks), strong vortex characters, b2b, slow walk speed, not as strong anti-air game, and lack of good normals for a good section of the cast.
The patch worked wonders though, and I the game wouldn't have seen Evo 2014 if it weren't for 1.06. Mr. Wizard even stated that viewing NEC was the primary reason he put the game in for a second year.
Surprisingly, even though I played Tekken, KOF, and MK9 this is the first fighting game I've really tried to understand how it works (especially the neutral aspects of fighting games) and my knowledge of fighting games has increased immensely because of it. The game was different, and I accepted it for what it was. I will still be playing it for a while, don't plan on dropping it until I transfer for college. Same goes for the other fighting games I play as well.
I will say I would have liked to see what the level of play could have looked like for injustice 2 to 3 years down the road. I felt the level of play for MK9 really peaked in early 2013 but was cut short, especially the DJT vs. REO match (personally one of the best display of footsies in MK9's lifespan). I feel injustice hasn't been explored fully in some aspects, especially when it comes to stuffing dash-ins, MBDC (FADC) to close down space, and potential uses for bounce cancels, trip guarding, and knowing the specific ranges for anti-airs. The game I feel still has a lot of growth for it, but at this point I can't see it growing any further due to MKX.
To sum up, good game for me, looking forward to what the future holds for NRS and this franchise. Injustice brought in a lot of new faces to our community who previously never new about the competitive scene. To me, I see that as a success, not a failure.