I'd wait a decade, see what happens with the classic liberal void. If Italy fills it, fine, then there may be balance after all.

If that doesn't happen, then joining means you get to participate in doing what the Germans and French think you should do. So unless it's a bailout, I would stay far away. Keep the economic treaties and Schengen - those were the things that started the entire concept in the first place (i.e. Benelux.) The rest is imperialism from underperforming large states that mostly just want influence.