The fact that NRS were able to amend the Batgirl infinite so quickly since it went viral (on TYM) shows that they are in fact monitoring Injustice and may actually care about the game to some extent however their quick response to the infinite does show one thing; it shows that they could patch the game with small tweaks like the hit advantage of a move anytime they want when they feel it necessary.
Although there is no denying that Martian Manhunter is the best character and people may commonly complain about the character, when it comes to Grand Finals at a tournament he is not winning like pre-patch Superman was, and the match-ups actually look like a fight even if it is in MMHs favor.
Every tool the character has may not have fully been intentional but the fact that up to now he has still remained untouched clearly suggests that they don't see anything wrong with him and neither do I to be honest because he's just yet another character that bodies Killer Frost
On a competitive level the Infinite obviously had to go to avoid 'killing the tournament scene' however the fact that a very niche amount of players are actually able to compete with Jupiter's Martian Manhunter shows that it is possible and that the character isn't ridiculous, everyone else just sucks at the game