Eh, a character with some 'Sue' or 'Stu' tendencies can be fine so long as you don't go overboard and keep them well balanced to be believable (And no, clumsiness does not counter the 'Sue'. I'm eyeing you, Bella. >.> ). There are some people though, who the moment they see OC, FC, or even CanonxOC/FC will go ballistic without even reading about the character or giving them a chance.