Don't. Meredith had already sent for the Right of Annulment, and she was going to search the tower and find necromancy research in Orsino's quarters. Mages would have been put to death even without Anders forcing things. His surprise action saved some mages.
It's hard to tell what exactly was Meridith going to do, and how to act, but it is true. And it's directly in-game, though it's easy to miss. She did send for the Right of Annulement. Red templar at Courtyard (whatshisname, one whom you can trick about mages being dead during Thrask's quest) states this once you click him and says that "those robes gonna get what they deserve soon"(not 100% accurate quote). I'm not sure if there are more direct evidences. But this one is.
I finished my second replay yesterday night. And I'm very annoyed by the fact, that I suffered DAA import bug - I did not have Nathaniel or any other sidequests, and I'm not even sure there were any differences at all between this and my first DAO import (same warden, alive, female, noble, queen, DAA - Keep upgraded, City - defended, Architect -dead, Nathaniel lives, but was not in final party). Some metagaming suggests that Legacy recognized DAA import (the way Anders talks about Sigurn). But other than that - nothing. And Anders lines did not change at all(which I was hoping for, actually).
Could I miss something? Is there any kind of list that shows all of DAO vs DAA import differences?
As for emotions and thoughts - I enjoyed it second time, shame there was no "first impression" amusement, but I liked it. DLCs are good, and headcanon is strong. Sad it's finished... And I'm not ready for another replay yet. And not sure about where to move next... Tetris, Bookworm or Bejeweled, may be right choice, because I don't think I have room in my head for more big games and stories right now, not before they finish DA3. 8P May replay kotor or some other oldie-goldie...