If you were to design a tone arm, what would it look like and feature?

Every connection in a wire creates eddy currents and micro-arcing at the connection interface. This distortion is particularly harmful in a tone arm, owing to the fact the signal from the cartridge is the most highly amplified in all of audio. 
 

The same thing happens with physical vibration. Waves traveling up from the cartridge, instead of being uniformly and smoothly dissipated along the arm wand and into the body and base, are reflected back at the head shell/arm tube interface. Which is aggravated by the need for a fastening mechanism.

So it turns out there are a great many technical reasons why detachable headshells (and arm wands) are a bad idea. 
Unless of course you value being able to readily swap cartridges enough to make it worth the sonic sacrifice. In that case you really should just use a two or 3 arm table. But there’s always people who want to believe in the free lunch, a much more likely explanation as to why we see this obviously inferior design even on high end arms.

Wait- this is a joke, right? Because "if money was no real object" then what am I doing designing anything? I thought that's what money was for- to be able to buy people to do stuff like this. When you get to where money is no object you don't spend all day fantasizing you just pay some dude and complain about delivery.

Especially when guys like Schroeder already figured it out way better than I ever could. Only, remember 'complain about delivery'? Schroeder's about a year out. Dang. 

Oh well, not to worry. I hear Ledermann's gonna start making Schroeder arms at Soundsmith.