Yes, or they will just yell "Well, don't let the door hit you on the way out, UK!" and live their lives without those annoying northeners which don't seem to ever stop complaining.
Well, when the UK leaves, the main countries are what they are de-facto now, ie Germany-France (and Italy). I don't think it can survive since it got to be a german satellites vs anything else game. And obviously i hope we soon leave it, although i suppose this will happen when the nice great war happens (but already after UK leaves things will be set for dissolution anyway).
And no, that is not wishful thinking. If i was in wishful thinking mode i would refer to east Germany being annexed only while Germany was an EU state, so following the dissolution it is an illegitimate state. Give it to Poland

Moreover set a muslim state in central Germany as well. Deus Vult.