If the front end in in good repair, anything less than racing on a track will not show any limitations of the front end. Even hard cornering is fine. It may not have the steering feel of a modern car, but no cars from the 1980s did, including Corvettes of that era. However, if you were to change/verify all the bushings, ball joints, and tie rod ends, made sure that the car has a proper alignment, good tires, and the better body mounts (i.e. not 35 year old rubber), for street driving, the car will handle just fine. As for the caster available with the factory upper control arms, the 3 degrees available is also par for the course for cars built in the 1980s, from any American manufacturer. Caster has increased in more modern cars, so if that is what you are after, have a talk with Firm Feel.
It must be kept in mind what these cars are, and are not. As I have written, these were not intended to be high performance sports cars. Even within the duration of their manufacturing run, the only car that may, and I stress the word may, have had any pretension to being a high performance car would have been the Cordoba LS/Mirada CMX, and they were only slightly oriented towards performance, and that was only in their first year or two. However, their competition, say the Monte Carlo and the Thunderbird for the J bodies of the same production year, or the Chevelle/Granada of the same years for the M body, were certainly not great handling cars, either, and I honestly believe that the J and Ms of those years were slightly better handling than their competitors. The fact that they can't handle as well as a modern car is more of things changing over time vs. a bad design. Newer suspenion designs have come along, and handling has more of an emphasis now than it did when our cars were in production. Back then, all of the manufacturers were looking for that mythical "Big Car Ride", and tuned their suspensions that way.
If in good shape, I don't see why any of our cars would be found lacking, if it is kept in mind the way they were originally designed.
The radius rod deletion, and the camber limitations actually created a controversy within Chrysler, and some of the suspension engineers even quit over it. But the transverse torsion bar suspension was used in millions of cars, and aside from the first year or so of substandard K members, has proven to be a good design. It was good enough to be used in hundreds of thousands of police cars for many years. It is NOT a sports car suspension; it was never designed to be one. It is a good, solid design for a street driven car, which is what it was designed to be.