I was kinda meh about WB. Very stong but pathetic against Kizaru who can avoid like ALL of his attacks. If it were up to me this is how I'd rank the roster.
Best:
Luffy, he's the main char. Obviously.
Very Good:
Zoro, (pretty much complete moveset that is awesome and powerful)
Anyone with boobs. Pretty much all of the girls are awesome and great for taking out armies. Nami's triangle and 2 bar Musou did more damage than WB's did at the same level) both of Robin's specials are great and Hancock has the ability to get cheap shots in pretty easy)
Good:
Usopp. As long as he has the Kabuto and his dials he's awesome. Earlier on not so good. Sadly no Sogeking option which is bleh.
Brook: His lack of music does nothing to hinder him. Unlike Franky. Also his specials are decently good too.
Meh:
Chopper: His Square and Triangle is more powerful than most specials are, and has decent specials (and the only great timed special in Monster Point) but overall he's not so good.
Ace: Weak attacks, bad and weak specials. Some of his attacks require him to 'recharge.'
Sanji: like Ace. Weak regular attacks and specials aren't too great.
WB: Powerful but sooooo slow, useless against pretty much every boss that can teleport (which is everyone)
Franky: Slow, not great for huge armies, Cola gauge pretty much screws him over
Dunno:
Jinbe. Just never played with him after his Log. Kinda felt he was thrown in the game after they crapped themselves and thought he was gonna be the new crewmember. Shoulda been Bon-Kurei instead.