A little from column A, a little from column B. The ending has a lot of issues from a writing POV: how much source has been gathered? How much is needed? How much does each individual sourceror have? How much does each individual non-sourcerour have? Do you need all the source or just the source of sourcerors?
Lucian even goes as far as to say that they only need YOUR source, SPECIFICALLY. Unless that's in regard to the whole godwoken aspect then that means they either hunted down all sourcerors EVERYWHERE or you have a proportionally large amount of source; none of which is explained. Definitely the weakest part of the game story-wise. Also the sort of person who can justify genocide to avoid a bloody war is a mentally ill person and the writers should have acknowledged that. I mean, Fallout New Vegas hit the "Man who wants the good ending and willing to do unspeakable evil to accomplish it" character straight on the head with Caesar, don't see why Larian couldn't at least emulate the same.

I think the reality of the situation is that the story writers dropped the ball, and the universe lacks consistency. At least they explained why the elves dying mattered, that they at least handled very well, but that is just one piece of the puzzle.

And I'll repeat until the end of time: Where's Amadia in all this? Did she have a brand change to Astarte or what? IT'S A STORY ABOUT SOURCE WHERE'S THE GODDESS OF SOURCE GONE? JAHAN EVEN ADMITS TALKING TO HER!

[Continues ranting forever]

Trap Strats: DOS1:EE? Cheese - DOS2? Mashed potatoes - Proper nutrition is key to dungeon delving.