As for his vocals (growls) in the early days... They were just OK, nothing more. But then, they were like the drums - playing second fiddle to the guitars and song structures. If they've chosen any of other hundreds and thousands growlers in the metal world, it would prob. still be fine, and without objection from the fans (not the NW - Tarja situation).
A good point, although I think Anders' vocals did enhance both Colony and Clayman. He was at his best during that period, imo, and I can't think of many vocalist who could have pulled off those albums better. It did destroy his throat for a while though.