It's not at all just cosmetic, unless you consider new renders and animations and completely redone writing and engine just cosmetic.Mmh ... ok ... not a fan that I have to start again, but ok ... So this is the final Chapter 1? and chapter 2 will be a new game? In these cases I always suspect that the decisions we make are just cosmetic and dont change anything ...
And yes this is the final of chapter 1, but it is "to be continued" into chapter two of course