just to put my perspective out there:

this universe/story is not about the past or exploring the changes of the world. yes, the characters are dealing with the changes they've gone through right now. that's what an introductory story is for.

once the team is settled and we move on to other stories, I imagine things will be different.

as for Grimm, I've tried to deliberately be vague about just what he does or doesn't remember. for all intents and purposes, he's a "new" character free and clean of any baggage. and I never said he was from "this" universe. so there.