you didnt answer though
why would the EU impose a really really crap trade deal (your words) on the UK and itself
The EU will seek to get as much value and benefit from any deal as possible; this is what happens in trade. Who knows what they might ask for in return for favourable terms to the UK? Yes I know the Uk buys a lot of stuff but equally it sells a lot of financial services to the euro zone. As I have repeatedly said this latter point is a strong bargaining chip for the EU and they no doubt know how dependent the uk is on financial services. And remember, it's 20 plus countries who will vote and who knows what agendas and beneftits they want.
The bottom line is I don't know....and you certainly don't as you'd be telling me how BREXIT will look....or at least have a thought out plan.