Yeah, online totally sucks. I usually call a friend up and we play opposing CPUs while bragging about how bad we'd beat each other. It's awesome. That functionality should be in Brawl.
Seriously, now, as far as music goes, several great video game songs were midis. I have no problem hearing some more, as long as others are orchestrated. They're offering more songs than we've ever seen before, so I certainly am excited that midis help to allow this.