Jo Johnson has helpfully crystalised the framing of the debate.
Its "vassalage or chaos" vs 2nd ref (or GE)
May survival is dependant on enough mps buying her threat that its her deal or crashing out. Johnson (J) is certainly not alone in rejecting that as a false choice.
As has been pointed out above - any deal that the EU agree to will be shit, demonstrably shitter than what the uk has already and nobody but May loyalists is going to be defending it.
The remain supporting media will take Johnson's position.
The brexit media will call may deal a betrayal.
Labour will vote against. The tory brexiteers will vote against. The tory arch remainers will vote against.
May will resign. A50 will be suspended.
A 2nd ref gives parliament a bit more democratic defence that just calling the whole thing off
The tory brexiteers can blame May and the establishment for sabotaging brexit from the start. they can call for a no deal crash out, knowing that it wont happen but leaving them with the ideological purity intact.
the labour party can blame May for making an utter fuck up of it leaving no option but to suspend A50 or face armageddon whilst arguing that they did their best to respect the ref result but weren't in power.
2nd ref may be bitterly resented by a big chunk of the brexit voting population - but id argue that the toxic legacy of brexit goes back to having a referendum on the first place which allowed people to vote for something that was impossible to deliver.
But then we have the very real possibility that leave wins a 2nd referendum - and oh the joys that will bring.