Is this designed around a Motion control card or solely PC software based?
A few that would be on my wish list would be a full complement of G codes and canned cycles for both mills and lathes, including G31 skip input for probing, also the ability for parametric programing.
A professional looking, unclutered operator interface (not something that look like a kids game), with paging menu's, preferably.
A position screen that includes 'distance to go'.
I will probabally think of others.
BTW what operating system?