I never played Bowser's inside story, but it sounds really good, so I'm all for it. It always kind of annoyed me how characters who have had voices just use grunts. Like, Marth speaks full japanese sentences, but Dedede just makes some strange grunts that sound nothing like his voices that he's had (although the only one I know of is kirby right back at ya).
Here's some chars who's voices bothered me:
Bowser: The generic beat grunts, as already said in this thread. But I do want to mention that I love how Project M devs slipped his Mario Kart 64 roar into his down taunt.
Mewtwo: His grunts were fitting, but I wish he spoke a bit like he did in the movie. Also like what the Project M did slipping his pokemon roar into the side taunts.
Donkey Kong:
DK 64 voice and grunts would've been nice. Or his voice from that DK country show where he sang all the time.
Diddy Kong:
His MK Wii sounds) I kind of liked his brawl grunts, but they weren't really accurate I guess. His Diddy Kong racing voice seems a little too silly.
King Dedede, as I stated above.
Ike: I don't even get Ike. He sounds creepy in brawl, and not much like hisfire emblem voice. He also spoke english when all the other FE chars spoke japanese?
Sonic: I love his "You're too slow!" quote, but god the rest of his lines kinda suck, especially when he says "we should do this again sometime!" I'd prefer his voice by Jason Griffith from
(Sonic 2006) and
(Sonic Unleashed).
Pit: His voice in brawl sounds so weird, can't quite put my finger on it.
I like his Uprising voice way more though, I even use a mod for that voice in Project M
Wolf: I actually don't have a problem with his voice, lol. Just wanted to mention that I love his voice in comparison to his Star Fox 64 voice...