I also enjoyed DSC as the alternate ending. It was fun to play an ogre and I fell in love with "grab." It was a little tough offing some of my companions (although it was great fun stomping on some) or otherwised cherished characters but all in all it was a nice change of pace.
Alistair most definitely did the ritual, otherwise Morrigan wouldn't be there
I got a great laugh when it turned out Alistair and Leli got together, I couldn't think of a more natural pairing.