The strongest argument I've seen for Brexit came from Tony Benn during the
Maastricht Treaty debate.
Quite how persuasive that argument is I can't say. I do think that arguments about the economy and policies are far more persuasive than arguments about democracy, and in that regard the Leave camp have a real struggle.
They can bang on about immigration, but that just opens them up to the charge of being racist hatemongers. I'm sure the more right wing Tories in the Leave camp would love to bring up the workers rights the EU protects, but I don't think '
we want you to work 60 hours a week' will be a vote winner. As for the economy, while they could reasonably argue as to the scale of the disruption, it'd be ludicrous for Leave to say there wouldn't be any pain whatsoever.