I think the biggest problem with Subspace Emissary was just how damn generic the whole thing was. After that, it would probably be the Kirby level design (the whole Smash series is pretty much Kirby Super Star as a full-on fighting game, and so SSE essentially went full circle and became just Kirby Super Star again).
Randomly, I have to say that I'd love to see Bomberman in, complete with cross-shaped bombs.
Randomly, I have to say that I'd love to see Bomberman in, complete with cross-shaped bombs.