In theory Europes borders aren't optimal. On the other hand redrawing them creates all kind of problems.
As far as Belgium goes, the French part could go to France, the Dutch part to the Netherlands and the few German town to Germany.
In Italy it seems like the South would get even more unstable when the North would get it's own country.
As far as the UK and Spain go, I think it's largely about them treating their minorities better. In both countries the last terror act driven with the intention of secession is a while back.
The internet weakens lanugages like Catalan and Basque. Young people are more likely to not want to align themselves with those languages and instead speak a more global language.
Germany works quite well without any of the Finnish speaking people wanting to secede.
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