Improvements to the quill lock on a milling machine.

[tonyfoale]

They'd been better off, compelled to front mounting; use a left hand thread for CCW operation and some kind of adjustment so it would lock without interference from casting.

Both good points. A LH thread would have cost the factory nothing. An adjustment system might have added a penny or two, but at least they could have provided say 4 to 6 positions for the handle.
In any case I have found no disadvantage with having a rear mount, I have used the rear mount for over 10 years.