Exactly. What's so complicated about it? Multiple Earths are the perfect solution - if something doesn't make sense here, it happened there. If a character (like Captain Marvel) only really works if he's got an Earth to himself, then give him one. If nothing works anywhere, retcon it out. The only difficulty is in figuring out who or what goes where. If anything, the Crisis made things MORE complicated for newbies to figure out, because now there are entire decades worth of storylines that don't make any sense ANYWHERE.