The 4wd won't make up for the uneven wear the tires will experience from front to back. The loads put on each are very different front to back as well as side to side. The front tires take the brunt of the braking load and turning loads. The rears definitely have it easier. Rotating tires on a full time 4wd vehicle like ours is even MORE important because the computers read tire rotation as part of it's program. Uneven tires will cause inconsistent rotation due to the diameters being off and the computer will not be ok with that at all. I've seen bad vibrations, error codes and cars going into "limp home" mode due to this. I don't mean to preach doomsday, just saying it's something that shouldn't be overlooked.