I'd think the biggest advantage to having 2-wheel drive would be that the truck sits lower, and most 4x4s sit too high for the 5ers we pull.
That said, I wouldn't go back to 4x2 if I could help it. I've used my 4x4 to wander along jeep trails for sightseeing/photography, wood gathering for the fire pit and fishing trips, steep driveways, stump pulling, towing stuck 4x2s and, most important, snow, ice and mud. Oh, and for those mountain passes with chain laws in effect... that don't require chains if you have 4x4/AWD. In other words, 4x4 is really handy for me, summer or winter.