I noticed at Tampa Super Show the Diesel pusher chassis near the entrance had much wider front tires. Picture below.
I think the main reason for the wider tires is that some of these rigs carry much more weight on front axle -- like about twice as much. Specs show front axles can go up to 20,000 pounds, much higher than the typical 9,000-pound axle in large Ford F-53 gas Class As.
I don't know if wider tires would help with handling (personally doubt it), but you'd have to run pressure very low by MH standards to avoid a harsh ride.
I have thought about it in a different context for a smaller motorhome. I like the idea of converting to single rear wheels and using same size tires in front to make all four corners (and spare) same size. Problems include wider tires may cause interference with chassis/body at front, ride would be harsh if pressure isn't lowered a lot, and some of these tires may not be rated for both steer and drive axles.