A - it's REALLY HARD To truly "balance" a fighting game - you either make it fun, and it's unbalanced, or stale and boring, but all the characters are even...
B - when rash horrible balance issues come out, responsible communities ban / create rules to take care of that... Sure, SSBB community didn't because they relied on the people WINNING to make their decisions, and well, they were all MK's
But usually, it does happen, and issues are resolved.
C - IMO, fighters have a huge stigma - of mashers vs intermediates...
It's really simple math though: mashers constantly hit buttons, so they are always attacking. An intermediate is trying to use what they've LEARNED, but that means - they aren't just hitting buttons, they are trying to get this one combo down, certain input, etc, etc...
...so while the intermediate is thinking, the masher wins. "Ohh, this game is BS, blah blah" ensues, and well, the masher never learns, and the intermediate stops where he's at and quits.
That - imo - is a big big stigma issue. Then, once you get good at a game, yes - tournament play is 100% different than casual. Yes, if a game has been out - there is a LARGE learning curve to get past to play with the pro's locally. Yes, one or several characters can give you serious issues. But, unless it's MetaKnight in Smash, for the most part, they are "Beatable" - you just have to practice / over come / adapt, etc.
Shooters have entirely different problems - but one of those isn't the netcode sucking. You can get on any time, and play against someone in a fairly fair environment - that alone puts a FPS over a fighter in ease of popularity and accessibility... Doesn't make them better, just currently the fad due to technology, etc.
X A