Nahhh..how often do you play against them? I practically forced my nieces and nephews (I've got 25 of them combined, about 15 of them I've played against) into playing against me or the CPU all by themselves at level 9's and handicaps at maxed. They get frustrated and complain they are to tough or I don't go answer on them. I never go easy on anyone when it comes to Console games for Television. So Brawl is no exception.
Although I do have friends around my age who are competitively good and uses Zelda/Ike/Roy/Marth/Link(Played both Brawl and Melee if you didn't get it), etc, as you see that they use the more skilled players, they are barely matched when I use Peach. However...They cannot ever come close when I use Fox. My madman.
So yeah, Crazy Hand was a secret boss.
Giga Bowser was also a secret boss in Adventure Mode and in the final event, which is Event 51 teaming up with Ganondorf and Mewtwo. Same requirement at beating Adventure Mode at a certain time, as well as only Normal to Very Hard is when you come across him.