I didn't think Anders was that bad of a frontman. Speed from Soilwork is much worse. M. Stanne from Dark Tranquility is the best of the Gothenburg frontmen. He was good live.
Unlike most IF fans, I liked RtR quite a bit, finding it much more interesting than Clayman, which had about four good songs and the rest was filler. Doing another album similar to that would have been a disaster. I pretty much lost interest after STYE. I don't think they ever sold out really. The albums progress in a rather natural way, just not an especially good way.