I personally like the Anora as queen, both you and Alistair live option, but that is probably because my human mage is head over heels for Alistair, so I can't make him king if I want to keep it that way. LoL I do think that the ritual would have to play a part if there was ever a "canon" ending, because I agree, it brings up the most interesting paths for future adventures in Thedas to take. I suppose canonically, Alistair being king would take the edge off of the whole problem of the kingdom eventually invalidating the function of the Grey Wardens, because clearly he would never do that, but I feel like if you make Anora queen, she comes to understand how important the Wardens are, so maybe that's just splitting hairs.
I am hoping that the expansion can accomodate the decision I made to make Anora queen and have Alistair remain with the Wardens. Since my character is a paragon of virtue, she really likes him.