Honestly if you just ignore Meta Knight and then play on a diverse array of stages (so you aren't always playing on Olimar and ICs counterpicks which is dumb and hurts the game's balance), Brawl's balance is fairly decent. Again just pretending that MK isn't in the game, I'd be confident to say that Diddy Kong, Wario, Toon Link, Zero Suit Samus, Ice Climbers, Pit, R.O.B., Kirby, King Dedede, Olimar, Falco, Pikachu, Lucario, Marth, Mr. Game & Watch, and Snake are all tournament viable characters. Honestly even with MK they're all viable; it's just that there's a strong argument that using non-MK characters is irrational in an environment that includes MK since he's the easiest to play and wins every match-up to at least some extent and some match-ups to a great extent. Add in patch support to only fix infinites and near infinites while not changing the balance otherwise and you could add Donkey Kong, Fox, and Ness to that list; all three have clearly "high tier" worthy movesets that are just shot down by gimmicks in small numbers of match-ups. Most of the mid-tiers are decent enough to use as well; it's not hard to find people who can be scary with Luigi, Peach, Zelda & Sheik, Wolf, Pokemon Trainer, Ike, or Sonic with some people being advocates that any number of them are better than commonly perceived (apparently the BBR itself is an institution that believes in Wolf!). Even your low tiers aren't THAT dreadful; it's really only Ganon who is a total joke. MK was a terrible mistake who really ruins people's perceptions of the balance, but just look past MK and you see a really diverse game. They know what a big mistake MK was I'm sure, and as long as we avoid that one towering character, I'm extremely confident in the dev team's ability to deliver a well balanced fighter as they did in the last two entries.
In terms of beta testing and such, a few things are being missed. For one, being a super strong player is not what you really need to balance an unfinished game. You need people to explore heavily and are good at system analysis, especially since pre-release testing is going to worry about all the characters. Remember how long the BBR tier lists lumped Ness and Lucas together despite how much wildly better a character Ness is; it's because of a tendency to focus on the top and ignore characters not seen as credible contenders for high tier (sadly Ness really was, but grab release was discovered before the reasons he's an otherwise good character). Also remember that early gameplay seemed convinced that MK was strong but fair and that Snake was broken; we know now that's backwards, and you have to be pretty good at picking these games apart to tell that Snake is going to fall and MK is going to rise in a more mature metagame.
The whole beta test thing has a bigger fundamental problem though. Nintendo just doesn't balance like that. They want the game to be "balanced" with a variety of settings and skill levels. In Brawl Zelda is a good case. In no items singles with good players, Zelda is pretty awful. Start changing some of those statements and Zelda becomes much more of a force; she's one of the best characters in the game in items FFA with bad players (as long as the one using Zelda is just good enough to hit with lightning kicks... which is a pretty low bar) and is generally at least somewhat improved by changing many settings (just going to teams and sticking with no items and good players really helps Zelda a lot). It's possible to make the game work across the board, but it's a far harder task than balancing a traditional fighter that only concerns itself with balance on one level. When you consider that Nintendo has these priorities and not just balancing our singles events in mind, I'd say how well balanced the previous games are speaks very well of them (and seriously, Brawl top tier or lose? That's not the Brawl I know). Have some faith guys.
To address the original topic, it would be nice if Nintendo supported events and such but I wouldn't count on it at all. Nintendo is just a very aloof company. This works to their favor in terms of making good games most of the time (they don't listen to the peanut gallery's endless stupid ideas), but for community stuff you really can't work with them. Luckily we have a lot of systems in place that let us work on our own, and if we work together with the new game, I think we can make things big on our own with at least a pretty good assurance that Nintendo is probably going to leave us alone.
