The problem stems from the Remain campaign being able to point to something evidential regarding what membership looks like, and Leave campaign (understandably in fairness) having to paint pictures as to what their solution would look like. This is just an inevitable consequence of the temporal dynamics.
Various advocates for leave of course told us that Europe needed us more because of budgetary contributions and that we'd get sweetheart deals, Liam Fox said trade deals would be really easy to achieve, we were told that we had special relationship with America (pre Trump - you don't see leave playing that card any more), Michael Gove assured we'd be OK and to take no notice of experts, Boris Johnson was exposed with his NHS bus in-situ but people still fell for it, whilst Farage ran his own immigration campaign with some incredibly questionable lines of finance behind it
A lot of people voted 'leave' on the understanding that they'd get a deal and then trusted the government to negotiate one.
Theresa May's deal is dead really. She can't keep bringing it back. She's like a grieving mother who keeps their child's bedroom as a shrine. The ERG are now seemingly adopting this bizarre position of stating that they think its a crock of shite, but are prepared to vote for if it's the only game in town. That's a seriously flawed basis to make any decision on, and JRM has now been exposed and basically take a position that confirms that his hatred of Europe is greater than his love of the UK
It should be a straight referendum between non deal/ hard Brexit and revocation of A50/ remain
There's no point putting May's deal to the people. It'll be rejected and there's no forward plan from this position. You haven't actually achieved anything. So then what? What comes next?