Why do I have such sloppy steering?

I agree with most here. If the shocks are suspect, then by all means change them out. There is a little bump steer that is worth bringing under control. It's an afternoon job, doesn't require an alignment, and will put you under the car where you can check the wear on everything else.

I'd start with replacing the bushings, then the ball joints. After either of these, have the front end aligned by someone who is familiar with TB Mopars.

The steering box may be worn out. Replacing with a FirmFeel unit will transform things.

I am hesitant to change the friction in the box, because I like to release the wheel and have the car start going straight. If steering effort is too light, go to a smaller diameter steering wheel. The factory Tuff wheel was 13½" in diameter and required power steering. I think the Grant repro is 15". Good luck.