Depends what you mean by a revamp. If we're going to see a ARR type of revamp (from 1.0 to ARR) we will need a whole new game engine. Currently game is limited by both engine and 1.0 code base. A new expansion will not fix that.

Mind you all of this is a huuuuge time and cost investment and SE as a company don't seem to be the kind that likes to reinvest in this game other than saving face for ARR.