Annoying for sure, in some cases realistic too! :D
I don't know if PhysX can handle wheel spin and loss of traction, as that would be the right outcome for driving hills too steep, not the agonisinly low speed, I remember countless times when either me or someone from my platoon drove their AMV stuck when trying to climb from a spot too steep, on foot it was still good to go most of the times.
When driving a wheeled heavy as hell vehicle, you can't just bash it around mindlessly, you need to plan your route carefully ahead, or you WILL be in trouble, not sure tho if implementing the loss of traction in Arma would be necessarily a good thing, could lead to some stupid skidding tanks like in BF3, urgh :mad: