Forget for a second the very real 'IT'S NOT GOING TO HAPPEN!' What would an EU be like with Russia a member/nation state? Would we all be friends? also, what would an EU look like with a Germany that has Russia to contend with for EU dominance?
Well, to get Russia to joint he E.U. the problem is trying to promote the E.U. agenda to the Ruskies. This could be for a more relaxed world, and, the leadership could relax more with the union. This would lead to a greater troop capacity in a world that needs troops less, as they will be richer with access to the Euro. There will be greater opportunities for trade and less problems with them trying to develop the lads they have too.
Germany wouldn't have it even if Russia did, Germany and France hate power sharing because Germany likes all the control, add Russia into the mix and Germany will feel less important.
I had hopes that would've happened with the collapse of the soviet union but russia wasn't stable enough in the early post soviet days and now has gone off the deep end of corrupt authoritarianism which would make it unacceptable to EU membership.
Then maybe they would lose thousands of years as being Russia, other names being used of course, and become a young European Russia. So, Countries Austria, Italy Belgium, Latvia Bulgaria, Lithuania Croatia, Luxembourg Cyprus, Malta Czech Republic, Netherlands Denmark, Poland Estonia, Portugal Finland, Romania France, Slovakia Germany, Slovenia Greece, Spain Hungary, Sweden Ireland, United Kingdom would be the new of each Country... Let's take Slovakia for example... So although Slovakia has all of this to its history, it is now a member of the New EU which was formed in... https://en.wikipedia.org/wiki/History_of_Slovakia The EU traces its origins from the European Coal and Steel Community (ECSC) and the European Economic Community (EEC), established, respectively, by the 1951 Treaty of Paris and 1957 Treaty of Rome. ... The Maastricht Treaty established the European Union in 1993 and introduced European citizenship. https://en.wikipedia.org/wiki/European_Union Who knows?? One European Language?
Europe should, but it won't, break up. The Schengen Borders Agreement will no doubt fail and be scrapped but the EU will continue simply because those in the EU Parliament they have their fingers in the Brussels coffers.
Putin is too authoritarian to submit to EU demands. But it would no longer be the EU. It would be the Eurasian Union.