This is written from my perspective as a German outsider.
In my opinion the EU needs a total revamp, i.e. a new agenda/plan in order to catch up with current econimic and political developments. In many EU countries people shift to the right because they see the EU as a bureaucratic and slow monster and beeing forced into things they don't want. I think you have to "de-europarize" some economic and political parts in order to account for that and regain sympathy for the european idea.
Merkel forcing other countries into things they don't want has to stop. For example If the majority of states refuse to accept more refugees it's their own democratic (not racist) decision. Period. There's no use in taking this any further as it will just shift people to the right even more and hate us Germans again.
I honestly wish Britain would truly become great again. There was quite a sell out of their own brands and industry and it appears (to me) the only thing left is the financial sector. It might feel as if they lost their identity and you need to bring that back somehow. That's what the Brexit guys might hope for.
I feel more connected to northern EU states like Britain , Netherlands, Denmark, Sweden, Finland, etc.. than any of the eastern or southern parts. Turkey is in no way european to me and they have proven many times that we don't share the same values. Both sides need to respect each other and that's it - but I don't see that.
In many ways the EU feels like a dead end and somehow on hold. Europe has to evolve in some ways... I can understand Brits saying it's no good for them but think something would be missing without them.
Merkel and other EU advocates have to realize and respect that the european people want to keep their own identity and representation. For example I come from the state of Lower Saxony in Germany and to me Bavaria is like a differnt country (like England vs Wales). We mostly feel more like Lower Saxonians than Germans but in football we unite.