Re: refused work visas .. And why would they do that?
One of the problems is that the outcome of staying in is also totally unknown.
The Eurozone is utterly doomed, unless something radical is done. Italy, Portugal, Greece and Finland can't survive in it, as currently constituted, and France, Ireland, Spain and Belgium (also possibly the Netherlands) can stay in, but at the cost of every boom being too big and inflation-y or bust being deeper than need-be. Or both.
Either there needs to be a solution involving pooling more sovereignty and some tax, spending and government debt - or a managed break-up losing some countries. Or it'll collapse - causing a hideous global recession, and possibly taking the whole EU with it.
The public are becoming more anti-EU in almost every country.
Cameron tried to get the EU to agree to take ever closer union out of the treaties. No one cares about it anymore. There are very few Federalists left in power. Almost no-one is working towards an EU superstate, the public no longer believe in it, and that generation of politicians have mostly retired or died. Germany are one of the most pro-Federalist countries, and certainly the only big country left with that opinion being mainstream. The polls still show this. Even though lots of them are unhappy with the Euro. Yet the whole tone of the debate about bailing-out Greece, or even Cyprus, Portugal and Ireland was bitter and very unpleasant. And showed that neither the people or the governments really believe they're part of the same group.
And yet they wouldn't give it to him, because that would imply a 2-speed Europe. Which we've already got of course. Us and the Danes aren't joining the Euro, we have opt-outs. Sweden promised to, but keeps losing the referendum and the Poles aren't even pretending to join anymore. Schengen is collapsing, and the core countries can only save it by kicking out the peripheral ones.
And yet apparently Cameron couldn't get a simple, basically non-controversial change through that would have made winning the referendum quite a bit easier. And that suggests that we'll again be faced with a bunch of new regulations to save bits of the EU that are currently in crisis - and told if you don't sign up we're screwing them all over. And forced into an unwilling choice to torpedo neccesary reform, or sign up to stuff we don't want.
Not that Brexit isn't also a large risk. But with the EU in it's current state, I'd argue there are no safe choices. And no ideal ones either. It's messy compromise all the way. At which point, I'm tempted by the messy compromise that involves more democracy, where if politicians screw up we can kick them out and get new ones who'll reverse it. The EU is good at new regulations, but quite bad at fixing broken old ones.