as someone that's been puttering his wheeler around on a single front tire for a while now (ford front axle with spool and I have only one hub locked), I can explain that one. When power is applied, the torque-steer is incredible and will turn the steering wheel in my hands. then, when I let off the gas, the reverse happens and the truck tries to turn the other way. not fun. When in 4wd, the effect is lessened.
But more to the point, I HATE MY FRONT MINISPOOL!!! straight-line traction is nice (as you might guess), but as soon as I turn the wheel, I hate it. If there's enough traction (you'd be surprised how often that happens on an otherwise slippery looking muddy trail), the steering wheel simply won't turn. (and if everything's bound up that tight, your posi-lock might not release. I know my hubs are a real pain to unlock). If everything is really slippery, the wheel will turn, but the truck won't always turn. Nothing like plowing in a perfectly straight line when you're trying to do doughnuts in the mud.
At first opportunity I'm dumping it for a regular locker. (It'd be in there already if those tiny hub bolts hadn't rust-welded themselves in.)