The only way the EU is doomed is if it doesn't get it's backside into gear over the migrant issue. Borders should have been shut down a long time ago with migrants instantly being returned to whichever country they attempted to enter the EU from.
I'd love for Germany, France and the UK to form their own EU which is purely based on free trade but not based on legal/political/currency aspirations. For me the EU has over-reached in allowing all countries to enter based on an equal footing even when their trade is no-where near equal. Internal migration borders should have been restricted based on proof of skilled/needed work or monetary independence.
The economies of the smaller countries that have either only got over their own dictators less than 50 years ago and or soviet dominance should never have been allowed on an equal footing.
The EU itself is an experiment that needs resetting in it's entirety and not just by one country leaving and letting it continue without a main member. Whether or not a reset would work is another matter and just an extreme thought from my little bwain