It isn't that I hate the soundtrack, it's one of my favorite in the series. It's just that the GBA can't hope to have anywhere near the same sound quality as the SNES can. Listen to the boss themes and the other themes in the video from the original soundtrack, then listen to them in the video again. You can't deny what a loss in sound quality it has due to being ported to the GBA.
In addition, I hope the game will actually be harder due to fixed bugs.