I don't understand this sentiment at all. In what way is balance less interesting?
What is there not to understand? I'm just saying from a spectator's point of view. You don't get as much wow-factor when you watch Fox vs. Fox. Of course the combos or the players playing as them would please the crowd but when someone uses a bottom tier like Mewtwo, it just becomes that much more interesting.
For example, Axe's Pikachu vs. Mango's Falco, Taj's Mewtwo vs. SilentSpectre's Captain Falcon, and Bum's DK vs. PC Chris's Falco.
Besides, I think it'd be stupid to repeat the same mistake - letting it stay beta for so long just to balance out the whole cast. A limited amount of open beta changes should be kept in mind so the metagame can start developing.
Basically, as hard it as it is to make everyone fall under one tier, but even if it is possible, I don't want that to happen. Having 3 or 4 tier groups is already interesting enough for me.