I've been outside of an English speaking country and I don't have a White Dwarf subscription, so I'm wondering what fluff has been written about Ulthwe after the EOT Campaign. I did manage to get my hands on US WD287, which has a little bit about Eldrad Uthran. Basically, he appointed a controversial successor, and then headed off into the webway and was never seen again.

Has GW written anything since then on what happened? Particularly, why was the successor controversial?