Exactly. The only problem is things like bumpsteer and ackerman, which also have to do with it. Bumpsteer should be tunable with a kit like the Bear kit. Ackerman, well I don't know, but I think it doesn't matter as much.
So, to get this straight - the shorter steering arm will allow those with R&Ps to regain their original steering radius? Is the issue with the R&P reduced steering radius the fact that it is pushing on a longer spindle than it was designed for? And pushing on a shorter spindle/shorter point on the spindle will regain that original steering radius?
Most racks have a 5-5.5" stroke, and therefore need a steering arm of the same length to get a decent turning radius (~30 degrees each way). Mustangs have a ~7" steering arm.
Besides the turning radius, the steering ratio becomes of course quicker. I currently have a quick ratio (16:1) steering box and the longer Shelby quick steering pitman and idler arms and I wouldn't want to have anything slower. I think many who have a steering box wouldn't mind quicker steering, especially those with 67 or newer cars, for which there are no Shelby pitman arms.
I have a Steeroids rack, which is already at 2.5 turns lock to lock, which is among the quickest out there, and I wouldn't mind it being a little quicker. No big deal there - it's not like I sneeze and am in the other lane at all.
I have to say (unrelated note) that having just replaced my stock PS pump that complained to high heaven at low speeds with every turn of my 245/17/45 tires, and was generally noisy anyway, I am much happier with the rack. The KRC power steering pump is pricey, but it steers like butta now. (but not too light) VERY nice unit.