There is no simple answer to this question. A game with a nicely restored cabinet and new decals would be worth more than one with faded art and separated corners. But I wouldn't expect a game with new decals to sell for more than one with original art in excellent condition.
The thing with decals is that they take a ton of time to do right. New decals pretty mean you're doing a full teardown and repair on the cabinet. The cabinet tear down, repair, prep and reassembly might be 20 or 30+ hours spread over several weeks.