Hollandes writings, tumbling economic prospects, huge unemployment levels, reported high numbers of google searches in Europe about the threat of civil war
If you want to have a sensible, fact based discussion you need to bring some proper sources and evidence to the table, not vague alt-right the-end-is-nigh stuff. The EU's economic prospects are not "tumbling" (you're 8 years too late with that forecast, and apart from Greece the PIGS are growing again - as is most of eastern europe, rather rapidly in some cases),
There is no doubt that the EU has issues - many of them in common with other parts of the developed world (slow growth, inequality, high youth unemployment etc), others that are particular to the EU, like the banking and currency issues.
But as others have said, the risks are not at all symmetrical. We have a pretty good idea what the risks of a hard Brexit are - the last few days have provided evidence that the remain side erred on the side of caution in their pre-referendum forecasts. The pound has already fallen further than many economists thought it would, and we haven't even left yet. Likewise the threat of inflation has reared its head earlier than most believed.
The main "risk" of remaining OTOH is that things will carry on as they are.
There is some banking/ currency risk but the UK being outside the eurozone is somewhat protected from that anyway. And the exposure it has won't be lessened by Brexit, as Europe will remain our largest trading partner (and if it doesn't then you will have far greater problems to worry about, like putting food on the table).