To be fair to Davis, he had no choice. There are 27 remaining EU members and they will set the agenda and most of the conditions. As Barnier has quite clearly stated, it's the UK which chose to leave. Nobody has forced us. The EU will continue. Macron and Merkel have indicated that they would be keen on reform, so it's ironic that the UK will have no voice at a time when the EU is improving. Even if Merkel isn't Chancellor after the German elections, she will be replaced by Schulz, who is even more pro-EU.
Ireland and Gibraltar are going to remain problems, to which there is no solution. May's days as PM are limited and the Brexiteers are digging a hole for themselves so big that hopefully they'll disappear before too long.
Hammond made it very clear this morning that he will prioritise the economy, so all those people who hoped for lower immigration and "taking back control" are going to be disappointed. It will get to the point when people will seriously ask "What's the point?", especially as there are 750,000 new, younger voters every year, most of whom support remaining. It's just a question of deciding when such a decision is politically acceptable.