KOF XIII is one of the more balanced games out there that didn't have a million patches (I think it had 3 though if you count climax). Even on a high level play it's possible to win with any character. It's been proven in tournaments all over the place. The influx of only playing a few comes with everyone seeing the new cheap tech. Monkey see monkey do is always in the FGC, but I watched just about every character make a top 5 at major tournaments. that doesn't happen if a game is unbalanced. Besides the fact is at a medium level play it really doesn't matter anyways. 3rd Strike is broken as hell tier wise and the character selection online is all over the place.
Working infinites in XIII really don't exist unless you count HD into neomax type combos, and the ones that do (Lightning loop, EX Iori Rekkas) are hard as balls to constantly preform. The worse shit I see is Chin HD combos or Duolon shenanigans, or just lag abuse in general all things considering it's minor.
The main problems were and still are:
1. Playmore can't get a good grasp of a good netcode
2. The people that mainly play Playmore games reside in Asia, Central, or South America. Ergo nobody near you plays
3. The tutorial system doesn't teach you set ups. Just how to combo. So someone who sits all day and learns the combos in mission mode and thinks he'll be hot shit gets blown up because KOF has always been an evasive game and all the vet has to do is punish someone trying to do the same jump ins over and over. Said person gets salty and bitches all day. Rinse, Repeat.
Personally I love the game, but I can see a lot of room for improvements. Like quit trying to be something that it's not. HD system was a ploy to get it noticed on the tourney scene. It's not something the game needed and if you took it out I'd bet there would have been a lot less bitching, and yes a lot less noobs impressed by it. However that's also why so many people hated it. Fun to watch, hard to master.