I understand what you're saying. Is your truck lifted? Roof rack? My XJ weighed as much as a lifted Disco, was on 35" MTZs, and had no swaybars. It cornered, stopped, and felt just as good as or better than stock. I've helped build other Jeeps that were tires as large as 42" that had no problems on the highway or off road at speed.
The thing I find is that most Rover guys lift and raise COG but don't go wide. That's messy. I'm assuming you're adding a larger front swaybar or a giant Jay Leno chin front bumper since you are suggesting you are going to be increasing understeer?
If you think a Jeep on 35's handled as "good" or better than stock, Jeep must have been making a really shitty vehicle. Maybe I'm jaded from driving around newer Land Rovers, but that statement just seems ridiculous. I guess Americans do know how to make a shit car...