Jaca, I agree it sounds good in principle but when resources "jump" it could leave you in the middle of a war suddenly (and through no fault of your own!) with fewer units or mass starvation. Loosing the city to invasion and suffering that problem is punishment for weak defence!!!! But a random jump? It would be nasty!
And I can see the threads now: Iron Jump ruined my game!!! etc.
Tell you what, give me an editor option (limited / infinite resources?) and I'm on board.