Tons of changes to progression with food.. re balance of stamina so you have to manage it better than at launch.. not much difference if you were careful anyway.

New weapons, new mini bosses, ride a lox, new armor, new area in the mountains with new resources.

If you are looking to extend from a previous save you will miss out on most of the changes. If you start over there is a lot that has changed.

So if you can handle it, it is there for you. Best experienced as a new character on a new save to appreciate all that was done.