The way I see it, there are really two options facing competitive smash players right now.
a) See Brawl as a disappointment, and not buy it. There is nearly no way to say this without being facetious, so know that I don't mean it such at all

. But I can't see why this would be a good idea at all. Honestly, it seems rather presumptuous to say, when the final build has been out for less than a week, that this game is no longer worth your time.
b) Buy Brawl. Brawl is gonna be a fun game no matter what, and is certainly worth any smasher's 50 bucks, if nothing else than to try out the super new characters, new stages, hear the awesome soundtrack, tinker around with stage creator, play other smashboarders online, and (for some) play SSE. Remember what it was like when Melee came out and you didn't know advanced techniques? It was a blast to play with friends, and just the sheer novelty of Mario vs. Pikachu was so fun. Isn't the fact that a new game in the series as your favorite game enough to make you buy it?
Which leads to my big point: the competitive scene hasn't developed yet. The new roster and the stage creator are gonna add to the expansiveness of the fights, no matter what. But the advanced techniques have yet to be discovered and developed, and we simply can't assume that they are dead and gone and that Brawl will be dumbed-down by default.
Remember when you were a kid, and you had something your parent(s) were going to make you go to on the weekend that you couldn't possibly imagine would have any redeeming qualities AT ALL? In that moment, you knew so clearly that the weekend was going to be the worst of your life. Lo and behold, that weekend the dreaded event turned out to have some things in store that were not as bad as you thought, and perhaps you made some friends or even had a good time! My point is, sometimes you will think you know exactly how something's gonna turn out, but your mind is just playing tricks on you. Forgive the analogy, I'm not calling you children, but please don't dismiss Brawl and pretend that you know exactly how the competitive scene is gonna turn out, in such a, dare i say juvenile?, state of mind.
It could turn out to be dumbed down a bit. Perhaps the game will only be fun for parties and non-competitive scenes, and times where you're dying to play as any of the very cool new characters. But there's a chance, perhaps not overwhelming but certainly not negligible, that Brawl will be as good as or even surpass Melee.
And, in my completely honest opinion, that's a chance worth EVERYONE on this board's fifty bucks.