I'm a long-time lurker on here, but I finally had to register, so I could give my two cents on this issue, as it's beginning to drive me nuts.
First of all, you "tournament" people say that the game was meant to be played the way you guys play it, with items turned off, and certain stages banned, as you have the ability to pick and choose the stages/items and whatnot that you can use. But lets think about it like this -- just because somebody gives you the option to jump off a bridge, does that mean you would do it?
Personally, I strongly believe that even though we have the option to strip the game down to a "bare-bones" version that is "more competitive," the game really wasn't ever meant to solely be played in that manner. I doubt very seriously that when the developers were making this game they had you guys in mind. If they did, then I'm sure that they would have had all items and "unfair stages" turned off by default. This game is not a Mortal Kombat or a Street Fighter. It's Super Smash Freakin' Bros. And the last time I checked, it was made by Nintendo, A.K.A. King of the Party Game.
If anything, I think it's the tourney-goers that could be in for a reality check come time for Brawl to come out. I'm pretty sure that the only way you're going to be able to play as Zamus is when you use a Final (after all, that's how it was shown to us in the trailer), and as for some of these advanced techniques, I wouldn't be 100% confident that they would make it into the next game.
IMO, to really be considered as a pro at this game, you have to learn how to play and embrace both sides of the game. I have no problem playing with items off and whatnot part of the time, but I also think that having everything turned on provides an exciting and exhilarating experience that matches your "tourney-legal" games.