My guess it will work a few ways, they said some quests will change and some you will have to redo as it will be completely redone.

So the stuff you redo, you wont get access to in the inn until done.

The stuff you have completed will have already new cutscenes anyway for the existing story and new players, so those will play as normal pretending its us (so expect us to sit in inns to see our old stories as new!).

It will be interesting tho, and the sad thing is they cant change to much without giving us the ability to redo, otherwise we'd miss out on a lot of lore.