scrub sees hilde dooming players left and right and is discouraged from trying to better himself as a player because he's convinced that he can't beat hilde, so he opts out of trying to play soul calibur 4
Though this reason has come up before, it's very subjective to who's watching and in what setting it happens in.
If someone saw this at a tourney that was all business, geared only towards getting the matches done and to switch to the next game, they might leave with such a bad impression. If it happened at a gathering with a good number of friendly players and casual matches going on, they might find friends in the game, and become more motivated to improve. From my experience in gathering new players on a college campus, people tend to see her uphill battle as a good challenge, no worse than certain characters in other games.
A few people have denied the offer to join in playing SC4 on campus; this was mostly because of their status as some 360 clan member, and their group plays nothing but Halo 3 and SF4 pretty much. They didn't want to put in the effort when they already had a group of friends playing a specific set of games, which I can understand.
EDIT@Something-Unique: I do think that the Bonus characters have no reason for being in the game, and I resent Shura and Scheherazade for having longer reach than their official counterparts, but from what little I've seen about them I don't think they can be considered game breaking.
I know their hitboxes are glitchy, but I haven't seen them magically escape combos like you just brought up. From what I have seen, their hitboxes are simply different (Kami-whatever can't use 44K in some situations with her shorter arm, her 33B tech traps in a different direction than NM, etc) but if they glitch as bad as you mentioned with escaping combos, my opinion of them would change to ban worthy, because then they would be more than just different.