Indeed. We've seen a lot of Asmodean, but we know very little about him as an actual channeler. He may have Talents, though we don't know of any. I suspect that, like Moghedien, he is an average channeler who learns only about what benefits him. His inability to break through a tied off shield is a sign of his mediocrity, because even Osan'gar says he can break through a tied off shield if he has time.

As for the War of Power, I'm of the personal opinion that there were as many as a thousand Forsaken at the time - though we only know of 13. We know that there must have been perhaps millions of channelers in that age, and if 1% of them were very strong in saidar or saidin, and some joined the Shadow, that would mean thousands of extremely powerful Forsaken. We also know that after the Strike, the male Forsaken who weren't at the meeting went mad and the females had to struggle for survival but died off during the Breaking.