OK, maybe all this really amounts to is a work around for the horrendously complex and inconsistent military interface (the military management SYSTEM is great BTW, but the interface is a nightmare). Anyway, I think it would be cool if you could simply turn on a designation for dwarves from 'V' mode that would allow you to designate them as military trainees. Then, a separate menu (in the military screen, or maybe the work management screen) would allow you to set broad standing orders for all dwarves marked as 'trainees'. For instance you could:
1) Make all trainees forbid or activate certain tasks en-mass. This way you could make them all do muscle-building work such as pumping, or mining.
2) Turn on sparring, etc., for trainees without making them join a squad
3) Tell trainees to use only wooden weapons while sparring, without having to make a training uniform and assign it to specific squads.
4) Tell trainees to train up to only a certain skill level, then go back to normal civilian life. Perhaps also switch training on and off when they get 'rusty', so they can take the rust off of their combat skills.
5) Automatically make any dwarf below a certain amount of professional skill levels become a trainee
etc. etc.
The main reason I would want to do this is that manually creating squads (which are limited to 10 dwarves) can be slow, and having to set up each individual squad specifically for training orders would be a pain in the buttocks. No doubt this whole thing could be made obsolete when the interface gets an overhaul... perhaps I am off base here?