Would it really be that great for the EU, though? After all, the UK was never particularly fond of the European idea generally and further integration (i.e. federalization) in particular, to put it mildly. My biggest fear is the UK might go back blocking just about anything that goes beyond simple trade deals.

So, imho, the EU would be better off it the UK simply rejoined the common market, but not the political union. We have more than enough dissent, as is.