I really love the music they chose for the trailer!
If I still had a Wii, I think the part I'd be the most excited about would be the modified single-player campaign. I don't have any friends who play Smash locally, and the only internet I have is public -- you can't just plug a Wii and TV up in the corner of a library, mind you. So, I think it is clear that trailers like this aren't for people like me. That's why I love Smash 3DS, and why it's probably the only version I'll own for a long time.
Still, good job, guys.