I don't get that either or why Joss felt the need to retcon so much of the old 'verse.
Comic fans and Buffy fans need different things. (I think this is the answer to everything btw.)

How was Warren so important to the story that he had to be brought back, whether Joss forgot The First played him or not?
But he's skinless!

I can maybe, sorta-kinda see what Joss was attempting with all if it if spec is right, but I don't see how it was worth it at all.
And so say we all...