>Any punitive or vindictive response from the EU will tend to reinforce in the minds of Leave and Remain alike, that leaving was the right choice.

Not for me - if I consider the treaty to have a lot of punitive measures compared to the deals the swiss or norwegians have (while blending out cries of british politicians of unfair treatment and statements of EU politicos as well...) it would move my position a LOT closer to leave. A structure having to resort to punitive measures to keep inmates in is a kind of prison, and I believe in realizing losses early or taking the the lumps and move on. Chances of me working with a group on biz reasons is much higher than with people trying to use biz as carrot and stick. So as long as it is not during a critical time like 6 weeks before release date I expect to be able to leave / reduce time / take a sabattical without prejudice. I am highly suspicious whenever quasi-religious beliefs like the "need to always grow closer" are voiced.
I was doubtful on whether day-2-day work would be living up Maastricht treaty principles - mainly on the fence, would have voted against the € but for entering the EU. Currently still far away from arguing pro-exit, but most of the post-brexit-referendum statements made me question that position.