Are you sure you know what you're talking about? What role(s) do you think he played in SFV and MvC:I, and what decisions were his?
Mike Evans was the MvC:I producer and Combofiend was the associate producer. Combofiend wasn't the head person. Also, if they're given a crap budget, it's not easy.
Yeah, the function stuff was silly, but they had to come up with responses that didn't throw Marvel under the bus, and hardly a big deal knowing Marvel was controlling the X-Men thing.
His function was also advertised as being that of a sort of FGC liaison who would relay community opinions on aspects of Capcom's games that were largely to do with the fighting systems and game mechanics.
Compare his impact to his predecessor in roughly the same senior management position - Seth Killian. Under his watch we got Street Fighter 4, a substantially more complex, thoughtful and dare I say, fair game. Under Combofiend's inarticulate, bumbling fief, we got 5.
You take the comments on "functions" while being in a way true, were still a complete misread the attitudes of veteran marvel players and fans of Marvel franchises. Then you get his interview on Best of 3 (also featured in a Core-A gaming analysis video about the cost of reducing the skill gap) where he touts the reduced complexity of SFV as being this great thing, completely failing to realise that what he's saying is complete anathema to the crowd he's speaking to. Then you get his appearances on Cross Counter, IGN videos and whatever else where he just comes across as a buffoon who can play Street Fighter just fine, but should not be in a managerial position to represent the interests of fighting game fans.
And the end of it all is that instead of doing just that - representing the fans, he became a mouthpiece for Capcom, serving no purpose other than to justify their worst decisions to a crowd that just wasn't having it.
For someone who calls himself "combofiend" Rosas oversaw production of a game where the possibility for self expression through custom combos was stripped out, and the core of the franchise was instead turned into a mixup heavy guessing game.
Somehow despite all this, SFV is still a good game, but it's the decisions that he chose to defend which kept it from being a great one.