I disagree, but if that were the case, the game wouldn't be worth playing competitively at all because it would be "whoever lucks out in round 1 wins because of CP advantage". If matchups are so important that player skill is frequently brushed aside, the game itself is broken and banning one character isn't going to fix it.
Well, it kinda is that way...
If two players are fairly equally skilled, in a tournament set, if you win the neutral, you pretty much won the match. Since your cps are more than likely wins for you in an equally skilled match. If you play DK, and I win the neutral, you'll take me to japes or LM (I play luigi btw). If I'm basically on your level, I won't often beat you on those matches with this character setup. After that I'll probably take you to frigate, which is a very difficult situation for you. Thats kinda the way the cp system works. Or take for example a player I'm very familiar with, he goes by infern angelis. He's an excellent "Ike main" by which I mean he more often than not plays snake. However, if you don't beat him on the neutral, you basically lost. Because unless you play a character that can beat ike on pirate ship, and you're way better than he is, he'll take you to pirate ship or corneria, and ****ing **** YOU THERE. Ike on pirate ship is one of the rare stage/character combinations that I think beats MK btw (it doesn't beat snake nearly as badly btw). Actually, I can't think of another one.
The other option is that if you take me to a stage I can't win on (luigi on luigi's lol) or play a character matchup I just can't do (luigi vs marth/meta/gw/d3) I have to switch characters to try and make it work. This leads to something of a paper/rock/scissors battle of "who does he play? where can I take him? what's my advantage?". Because If you take luigi to japes with DK and I just happen to side falco, lol glhf with that.
The problem is, this **** does not work with MK. If you lose to MK, you take him to your best stage with your best character and hope for the very best, because it's essencially a replay of the first game. MK does not have bad matchups or bad stages. So you're at very most, going to get an even playing field with him (DK on brinstar would be somewhat even). If you play really well, and win, you get to go to MK's counterpick, which is likely RAAAAAAAAAAAPE. If you live in the midwest, like I do, you get taken to distant planet, and get shuttle looped all day. Other places you might get taken to frigate and get gimped, LM and get tornado'd to 80, Norfair and not be able to touch him, etc.
So in matches, really, in brawl, if you lose the neutral, 7 or 8 times out of ten you lose the set. Thats just the way it is.
Unless you're playing meta, in which case, 3 times out of ten you get to take him to the third game. At this point you get the opportunity to pull off a ****ing miracle. Good luck.