Does you deed say anything about plowing or maintenance of the road?
If the argument against removing the private loop is "it's always been that way" then why does that not apply to the changes that are now being requested, ie if the driveway plowing was always split equally then "it's always been that way and why change it"
The owner of the property you cross can charge you anything they want, as long as it is less then ZERO. If you have a deeded easment or ROW across his property then you have more rights to the piece of land than he does, you are the Dominant tenant for that section of his property. He can not put anything or do anything to the section of his property that has the easement that will block you usage of the road. He owns the property but not the road, an easement is not a toll road. If he wants to charge for mowing his lawn for you then tell him not to mow it.
AS for potholes and such, I"m pretty sure that all parties that use the section of the roadway are equally responsible for costs to repair it, but getting each to pay their share might require legal intervention through lawyers and courts, ie $$$$$. The person who owns the property that the road crosses is not responsible for providing YOU with a maintained roadway, it is your easement so it is yours and other who use that sections responsibility to maintain the road surface for your use.
If the plowing issue can't be settled then why not just tell the others that you want out of the group plowing and contract for your own plow guy to clear your section only?

