Wasn't the Nevarran Circle wiped out too?
In the rebellion? Perhaps. The Starkhaven circle was destroyed during act 1 of DA2. It had nothing to do with mage rebellion, Just free marches being a shitty place like always.
Is that really how you see him? Yes, he's a boring goodey two-shoes, but he still has a decent heart. He didn't want to rule Starkhaven because he was unsure about what kind of ruler he'd be. Now that the worst has happened he's finally doing something.
His kind heart also comes from his immaturity like children. I did dislike him but I saw it. He wouldn't have act the way he did if Elthina was not in that explosion. If he wants to be a good person and a good noble he has to care for everyone and tend to his duties not just his selfish motives that can and does harm others. He is willing to crush everything even romance if you don't kill Anders and then goes to invade a city. This is the annoyance we had to endure with Alistair as well but ten times worst. At least Alistair doesn't raze cities and can be persuaded to marry Anora and become king while you let Loghain live. That is my favorite world state for DAO.
I chose not to recruit Sebastian and let Anders live, I'm curious how that turns out. Besides, Sebastian was pretty useless in combat anyhow, only took him to his personal quests.