Actually, I want to note about my last post that Ics v G&W are probably pretty skewed as well, but the same occurs on Rainbow Cruise. That's all heh.
Also, I'm doubtful Mario is top. He definitely is much better, and likely upper mid-high, but we will have to see how his matchups pan out. A2ZOMG, you should break down his matchups in BBrawl. Preferably aim for the extremes; his worsts, his best, and his most improved.
The only matchups that Mario clearly loses are vs G&W and Marth in BBrawl.
vs G&W and Marth, those were basically the two matchups where it's difficult for Mario to either camp or be aggressive. These two characters also are very good at edgeguarding, and while the lack of RCO lag DOES help, their superior zoning game is still a major issue. Most of Mario's other matchups he lost not because he had trouble doing anything, but because he was much weaker than his opponent and it took longer for him to score the KO.
Mario was mid tier material in vBrawl, and underrated. Mario should have been just under Wolf in vBrawl. The matchups he had in that tier were for the most part very even in high level play, only slightly disadvantaged sometimes due to Mario having a little less reward on some key moves. By the way, Sonic doesn't belong in that tier, and Sheik was way ahead of that tier in vBrawl.
As for characters that are above that tier, Mario also did really well against Donkey Kong, Toon Link, Pit, Pikachu, Falco, and Diddy Kong in high level play in that those were absolutely winnable matchups that were close in high level play (if I recall, TC1, one of the best Mario mains on the WC, never loses in the Diddy Kong matchup). Mario even stands a chance against the Ice Climbers, as he actually DOES have the tools to separate and destroy them.
As for the Ice Climbers, let me explain something that should give you an idea how many options Mario has. What Mario could do in this matchup was D-air, and never get shieldgrabbed as long as he never messed up his spacing on that move. His fireballs COULD outcamp them. Cape ***** Blizzard and can sometimes beat Squall Hammer. The point I'm trying to make is that Mario always had a great movepool that could do good things under a smart player. Mario's main problem was he was a much weaker character than most.
Vs Metaknight, despite getting gimped a lot, can be manageable for the simple fact that Mario has great tools to handle various things MK can do. Up-B can beat the Tornado. F-smash can outrange MK. Fireballs don't clank against MK, so are spammable.
Vs Snake, the matchup becomes manageable when you set up gimps with F-air. Fireballs are still useful against Snake's lack of ways to stop them. Juggling combos are good against him as ever. In vBrawl, he just KOed Mario 70% earlier and did the damage of 2 B-airs with 1 F-tilt.
Most Mario mains say Mario beats ROB. I think it's an even matchup. Either way, Mario does extremely well against him. Mario has the tools to pressure and combo and camp ROB effectively.
King DDD was actually somewhat winnable with the infinite. It could be mashed out of, and fundamentally, Mario could be campier in that matchup. Mario's Cape and FLUDD also happen to be very good at edgeguarding DDD, and Mario's D-air again doesn't get punished out of shield when used correctly. Again though, the problem is DDD living about 90% longer.
As for Mario's favorable matchups, Mario pretty much dominates low tiers, having advantageous matchups against even guys like Ike and Bowser. My opinion was that Mario was too good for low tiers from actually attending a low tier tournament.
Fundamentally the reason why I see Mario as top tier in BBrawl is because he has all the tools for doing stuff you need to do. He can shield pressure safely. He can rack up damage pretty fast. He can camp. He can long range poke (with F-smash). He has SAFE KO moves. He also has a very formidable out of shield game.
He's not an overcentralizing character by any means (similar to the way Marth isn't overcentralizing). He's just easily one of the most solid forces in the game when played correctly in terms of pressure, damage racking, and KO options.
At any rate, Jab canceling with Mario is seriously amazing. His Jab cancel game is on par with, if not better than Luigi's, as you have two reasonably reliable KO options from it. Jab cancel D-smash and B-throw pretty much can guarantee death to anyone as long as Mario picks right, or has enough of a frame advantage from landing Jab (actually, Mario I believe gets a big enough frame advantage window against the entire case by landing both Jab1 and 2 that is large enough to land D-smash). In fact, I just realized that Mario probably can Jab cancel D-smash Marth and G&W before they can block. Considering the increased power of D-smash, that should be pretty scary.