From what little Baldurs Gate I've played the one thing I'll say is that I never thought about not hearing a character's dialog if you pick one of the pre-made characters.
I know that should be pretty obvious but, look I picked The Dark Urge because, c'mon. Needless to say I didn't know he was a Shakespeare character until later.
Some friends wanted to start a multi player thing and technically I'm not that far in so I may just wait and remake a custom character.