Spectator mode would be great. Last night I had to run a play-by-play to settle a disagreement that a room of us had regarding Yoshi vs. Ashi. (Ashi for the win!)
Ubuntu's "Spirit Assistance" shouldn't cause ties. In many ways this is a "Sudden Death" game. Sure, if two fighters knock each other out with a simultaneous blow that's one thing, but Spirit Assistance hits later.
If we only have one choice for something (i.e.: only one other character to switch to, only one character not killed that can switch in, can only rest b/c we're stunned, etc.) why not automatically do it for us? It would be simple and would help the game move just a little faster, especially when it's the opponent who only has the one choice and they dawdle.
Now that I have played more games it'd be nice if I could switch the three cards I was given as a bonus when I started. I had no idea how the cards I chose would help and while I've used some of them I'd rather swap at least two of the three out.