He makes some very dodgy points, although I'm not sure all of them are dodgy:
1. Fair enough, although it may perhaps be an irony of the UK's leaving that the rest of the EU will become "ever closer" rather faster than it might otherwise have. How ironic if we found ourselves with a "United States of Europe" on our doorstep precisely because we were no longer there to prevent or delay that! This isn't necessarily a refutation of Hague's point, but I do think it's worth noting that Brexiteers have perhaps underestimated the importance of the UK in terms of keeping EU expansionism somewhat in check.
2. I think the entire "control of our borders" argument was bogus, but I can't be bothered to labour this point.
3. 15% of our GDP is still a lot, so it's a bit much to write it off as not worth fussing about.
4. Here he's probably right -- no matter how true it may be that the deal on the table theoretically locks us into the EU indefinitely, I think both sides will look to resolve the situation before then.
5. The final line is utter tripe: MPs should vote on the merits of the deal, or otherwise, and not be trapped into voting "against the other lot". I agree that Corbyn's position (if not Labour's as a whole) is very dishonest, but so what?
6. I'm not sure I exactly agree with this: the government certainly has a duty to *try* to implement Brexit, but there may come a point where doing so is out of sheer bloody-mindedness. The primary duty of Parliament is to act in the best interests of the country, not just follow a course come what may, if doing so is damaging.
Now, having said that, I think it's fair to say that rejecting this deal shouldn't *instantly* lead to a rejection of Brexit. It may be that, after all, there is a fourth way, and that the EU27 blink at the last moment in a way that allows a slightly more reasonable deal to be reached just in time. But the essential truth of democracy is that no decision can ever be held irreversible, and there may come a point where after all the only sensible option in the interests of the country is to revisit the decision of 2016.
7. Also tripe. Brexit is bigger than who sits in Downing Street.
8. If we did change our minds, I'm pretty sure the rest of the world would take that in their stride too, so... I'm not sure what point he's making here, frankly.