The day off between matches will work in his favour, but the fact that slams are best of five sets will work against him.
I'd suggest that if he wins a dramatic and lengthy five-set match against a tough seed on say a Wednesday, the chances of him being fully recovered and ready to repeat again in the next round by the Friday are very low. And the chances of him winning seven best-of-five-set matches in two weeks, which is what it takes to win a slam, is extremely low. IMHO the only way he could win Wimbledon is if every match is easy and he wins them all quickly... but this doesn't seem that likely. There are some tough grass players out there, and it's difficult to break serve on grass, which can make matches longer.
I should add that I'm from the UK, and desperately want Murray to win... but can't see it happening.
I still think that one day of rest means more than possibility of 5 sets. Especially if he manages to keep matches short.