I know a lot of you guys track and autocross these cars without swapping out to some blasphemous rack and pinion nonsense. I'm just trying to figure out how far from optimized my steering is before I considered anything drastic.

So I had no illusions that a swap to a 16:1 manual box would suddenly turn the Dart Sport into a Miata but boy does it still suck.
I picked up a fresh/reman ebay large sector box...I was dismayed to discover that it feels very much like the power steering box that it replaced (when the pump wasn't running).

I've already swapped out the whole front end, upgraded to QA1 upper and lower arms, fresh lower ball joints, Hotchkis shocks, 1.14" torsion bars, Helwig hollow sway bar... I think I've done almost everything with the exception of tie rod ends and the idler arm (which I have on the shelf). I also have a 330mm Momo wheel with a suede grip. I recently had US Car Tool torque boxes and Mopar Performance subframe connectors welded in. K-Member is stock....

Numerous times, I've attempted to adjust the steering box tighter and tighter. It's somewhat better but still miles from "tight" or "sporty" and I don't know how much more I can tighten it down or if this doing so will would accelerate wear. Currently, there's 15* of play on center which would be ok except that it transitions directly from "loose" to "fully coagulated" once you start imparting an actual directional change. Steering the car through curves feels more like "bumping" the wheel back and forth, making digital adjustments.

I don't think it's dangerous but it's not enjoyable and it would be miserable on a road course.

Any suggestions about what to try next?
How good can the stock style steering actually be?

call firmfeel or try and get a borgeson box

I'm about to replace a Firm Feel stage 3 box with a new Borgeson/Bergman kit. This is in a 71 Satellite Sebring. I can let you know how it goes.

My son's Barracuda had manual steering when we first built it. It felt fine (it was a good condition used 24:1 box), but at the first autocross it was a handful, but not because it was hard to turn. It was just too many turns lock to lock. We found an old Diplomat police car and built a police car valved box with it and a small sector box. That solved the turns problem. The problem with a lot of the rebuilt boxes is that worn out parts were used and less than ample care taken when putting them together. You either need to do that yourself or used somebody like Firm Feel...

I have used Factory 16:1 boxes in cars for years. My opinion is they’re excellent. Smooth, fast steering.
If you have 15° of play, somethings wrong. Not clear what you mean by adjusting the steering box tighter and tighter, but I assume you mean you’re adjusting the sector shaft gear mesh. Most probably either the bearings are not adjusted properly, or it was a bad rebuild and you have worn parts.
Attached are the service manual pages on how to adjust the steering box. You need to follow these directions carefully; you notice that the torque ranges for the bearing adjustment is narrow. You need to use a torque wrench. You can’t do this by feel or you could damage the steering box.
If the box is in decent shape, and you can get it adjusted properly, I think you’ll find a massive difference in performance and feel.
Good luck. Take it slowly and carefully and hopefully you’ll get something that’s fun to drive.
Robert