I understand, but are you guys the rule or the exception?
How many Axis/Vegas owners actually tow more than a toad? Many I see have nothing behind, and the rest a car. I’d bet most can get by fine with 5,000-pound tow capacity. Need to tow a heavy race car trailer or heavy boat, etc. must be a statistical abnormality which shouldn’t limit design. Those few can always buy bigger F-53 motorhome.
And for what it’s worth, even Single-Rear-Wheel E-350 can tow up to 10,000 pounds if not loaded down, so the solution can be to make motorhome beefier (E-450) or make them lighter.
If Thor (with Hymer engineering help) can get weight of smaller Class As on E-350 chassis under 10,000 pounds loaded, that leaves over 8,000 pounds for towing.
All we have to do is look at how many Sprinter Class As and Cs have been built on 11,030-pound chassis to see there is a market for that size rig. For the vast majority of buyers in the 24~26 foot range, 12,500-pound GVWR should be plenty if motorhome is built on a diet.