From my perspective, Madden has historically (late 00s) endured problems due to inconsistency in game design. The best examples of this are the first few games on the 360, the game couldn't decide what it wanted to be. It had some elements of wanting to be a simulation, but juxtaposed with the implementation of weapons, the emphasis on RingBuilder, no concept whatsoever of teaching new users how to play the game, and an overall focus on the competitive online scene over all else, it was quite reasonable to question just how much the football actually mattered to the game Tiburon was making, vs. just wanting to make a culture piece and something for established tourney players, without making much of an effort to cultivate the Madden community on its own merits because, well, it was Madden and they didn't need to.
I think that Ian Cummings' team's lasting legacy on Madden franchise was redirecting that focus away from that online-only focus into in a direction more oriented towards realism and accessibility. Varying degrees of success each year, sure, but put any Madden before M10 side-by-side with any Madden after M10 and IMO the difference in overall cohesiveness and quality of the two eras of games is painfully obvious.