The biggest traction problem in a MH is the straight highway tread on the drivers - that's why they get stuck on wet grass. When you change the rear tires, get a slightly more aggressive tread. If they make any more noise than the normal (almost) slick standard tires, you won't hear it over the DP anyways. And yes, they may get just a few less miles than a normal highway tread, but they'll need changing due to age long before you wear the tread off of them.
I've been on a lot of wet ground and in a couple of inches of snow with mine twice and I sure appreciated them. Did the Continental Divide up at Steamboat Springs in a snow storm this spring. We pulled off when we found a good spot, but didn't have any problems getting to a pull off. Left the MH up on top and took the Jeep down to Steamboat for the afternoon to eat and look around.
Bill