Note, that everything in this thread is my opinion and nothing more. And while my opinion is heavily reinforced by logic and fact, it is still my opinion, and anyone else is entitled to whatever opinion, as flimsy and nonsensical as it may be.
Now that that's out of the way, the following is a detailed list of how I think SSBB should be. Note that, however it does turn out, I'll probably still buy it, as SSB and SSBM are two of the most fantastic games to ever be created and I don't doubt that, no matter what, Brawl will live up to that legacy, even if every single thing I say here is completely blown out of the water on December 3rd (not bloody likely, since Sakurai's an intelligent man (and pretty **** attractive to boot) and knows how to make a good game, but anything's possible).
First off, "wavedashing". I have no doubt in my mind that this technique (or, glitch, really) should be completely removed from the game. It just doesn't serve any practical purpose. I've seen it used in matches and referred to as an "advanced" technique, but the only reason it's in use is because every one else uses it. If it weren't there, I assure you, the majority of players would not miss it. It's a glitch, and it shouldn't be in Brawl.
Next up, items. Items are part of what make Smash Bros great, and the fact that it seems to be a prerequisite that they be turned off in tournaments (this is what I've heard) leaves me aghast. Items add a special thrill to the game. The fun of picking up a motion sensor and tossing it on to the ground and then giggling like a schoolgirl as the opponent steps on to it and takes a nice long trip into the sky, the suspense of throwing a Pokeball, accompanied by the laughs of triumph as Lugia bursts out and rains destruction upon the opposition or the cruel jeers from the opponent as Goldeen emerges and worthlessly flops about, or the awe and wonder as Mew appears, quickly followed by annoyance that it didn't do anything. Or, and this is my personal favorite, the horror etched into the opponent's face as Marth, Link or Roy pick up the saber and proceed to bring sweet sweet twin-bladed death unto all that oppose him. And all the other wonderful little treats in between. If the characters are the heart of Super Smash Bros and the stages are the body, then surely the items are the lifeblood. This is why items should never be banished from a match, because when the blood stops pumping, the body will surely wither and die.
Now, while we're on the subject of items, my journeys through the intarweb have shown me that some people are rather displeased with the concept of the Final Smash. This just utterly befuddles me. In my opinion, a system like the Final Smash was one of the very few things Melee was missing. A quick fact check will show you that pretty much every decent fighting game in the history of time has a Super system. One could make the argument that in the 64 Smash Bros, that was the vastly overpowered throws, but that is neither here nor there. And Final Smash is another example of the SSB series doing a better job than all of its fighting game predecessors. No obnoxiously convoluted button combos, just have enough speed and timing to snatch the Final Smash ball out from under the opponent's nose and then let 'er rip (and I will bet my hat that it will take a lot of speed and timing. If there's only one per match, then you're gonna have to be pretty fast to get it before the other guy).
In specific, I've seen a lot of naysaying on Samus's Final Smash, essentially confirming that an item is required to make the transformation to Zero Suit Samus. I for one think it's a great idea. Yeah, sure, the transformation system for Zelda/Shiek was good enough, but for one thing, it wouldn't make any visual sense for Samus. So she can just shed her armor and put it back on at will? Psht. Yeah, that makes loads of sense. Secondly, this is better in the fact that it makes Samus a deeper character. You'll have to learn to train as both Samus and Zero Suit Samus, and if you do this well, it would make you a force to be reckoned with, to be sure. Imagine it, you use Samus's already formidable repertoire to batter the opponents until the Final Smash ball appears, obtain it, and use her Final Smash to send them on a one-way trip to the brink. Then, with you're increased speed (and new sexy figure, rowr), finish them off before they can get their heads back together. Certainly, it wouldn't be an easy thing to master, but it would be oh-so-worth it at the end, I believe.
As for the stages, (the "body" of Super Smash Bros, I believe I called them) while I can appreciate the simplicity of Battlefield and Final Destination, the insane regularity with which they're used is...somewhat disturbing. There are loads of stages, guys. Don't be afraid to branch out. A good stage makes you consider the terrain and either be wary of it or use it to your advantage (Mute City). A great stage will constantly keep you on your toes, either due to inherent peril, or because you were just given a narrow opportunity to open a can of whoopass, somehow (Brinstar Depths, for example). Of course, the fact that these two stages are banned from tournament use is quite startling, as they're two examples of great design, especially when they're turned away in favor of Final Destination, which is, quite literally, just one long platform. ...Seriously guys, let's have some variety.
And this is an utterly personal thing, but.....Viewtiful Joe should be playable.
That's all I have to say. I hope you enjoyed reading.