To each his own I guess. The Witcher is one of those rare RPGs these days where by design you play a character with a sizable amount of predefined identity. As for the voice actor though, it seems as though his voice is the same in TW1 and TW2. Though TW1's ending cinematic has an unintentionally funny part where Geralt and a completely unrelated character(random servant of King Foltest) have the exact same voice.