What's funny though, is that I've played Smash LITERALLY 100x as much as Guitar Hero 2.
And it's difficulty isn't really the reason that I want it out. I want it out because it's an exploit of the game's physics and isn't natural - i.e., it's something that would seem stupid if it actually had a dedicated button and had been in the instruction book from day 1 (really, you can't deny that). I was just responding to people scoffing and saying that it's so easy a 5 year old could do it.
The thing about unintentional physics malfunctions (this is a general statement, so please don't pick it apart) is that most great games have them, and they are what add so much depth.
Some old school FPS junkies may be familiar with bunny hopping... An exploit of old first person shooter game engines. Bunny hopping was never intentional, but it added depth to the game. It would sometimes cause uproar in the various game communities, but it was eventually embraced, and became a staple element of games like Team Fortress Classic.
The skiing in Tribes wasn't originally intentional, but it became one of the games greatest draws.
Fighters too, have instances of game physics being manipulated to add depth to the game. Sould Calibur 2 had a fairly significant competitive following back in its time. A common term in the SC2 community was "Just Frame".
Just Frames occured when a characters attack animation would alter how the game saw that characters stance.
For example, some characters, when performing a jumping forward attack, would register as having their backs turned to the other player for one frame.
A button input on that one frame would cause an instant "Just Frame Attack".
This was obviously a glitch, but it added a whole new level of mixups and mind games that gave SC2 a whole new layer of depth.
Some people complained about it... But again, after a little while the community embraced it as being just another trick that the expert player could add to his arsenal.
StarCraft, probably the most successful RTS in the world, has several small glitches that are openly accepted on the pro gaming circuits. Drones, or worker units, can be glitched through mineral lines to be used as scouts, or to build forward bases. Units can be stacked to spread out the rate at which they take damage, and to concentrate their firepower. These are all glitches, unintentional in the games initial design, but staple to the pro player who has already mastered everything else.
Ultimately it's the community that decides what glitches are an aren't acceptable in competitive play. The game designers will never catch everything. And sometimes, they will catch things, but end up leaving them in place due to either time, or the fact that it adds an interesting mechanic.
Try to embrace gamings little quirks. If you play competitively, they allow you to keep up with the rest of the top gamers.
If you don't, then don't worry about it.