First of all, no offense to the person who did Oak's voice-over, this is merely my opinion.  I have no clue if these are just temporary game assets being used in the beta or what, and if that's just a placeholder (please let it be true) then simply ignore what I'm about to say.

I think he sounds like a complete panzy.  Normally I'm fairly tolerant of this type of thing, but if I was going to be serious about playing that character, I'd have to play with the voices completely turned off, it's that far off of what I would imagine him to sound like based on his appearance.  I'm thinking something much more like the Omniknight voice (Human Arthas).

Will it be possible to replace the game sounds with custom sounds?