The wheelbase on both is within half a foot, and at about ten feet long apiece for two axle units I really don't think it's that bad. It's really not that hard to widen out a turn or wiggle forward if you need to.
Why buy Class 7 city units for some barns and not others? The Class 7's are less versatile overall, however in areas with low obstacles a tractor with no fairings and a low-height trailer may be required. They are also more fuel efficient for doing what they do. That said, it's not a practical expense to purchase separate city units for every single terminal in a 300+ terminal network.
LTL carriers have been doing this for years. There are city guys at YRC driving road tractors that were retired 13 years ago. CF had road tractors from the 1980's in their city fleet when they went out. But in metropolitan areas LTL carriers try to have some dedicated city units.
Frankly, the only city drivers I have ever heard whine about not having a new, dedicated city tractor because road tractors are too big and too clumsy work at FedEx Freight. Most are happy to have a tractor less than five years old with less than 600,000 miles on it. Sorry if maybe nobody's taking you super seriously, but you have it pretty good here where equipment is concerned.