A mode where in the training hall, if you turn it on its almost like a lockdown match. Except no bases. Since its training no prizes or money. I'm sorry if someone posted this already, I don't read suggestions much. It would also have a tier 1/2/3 filter.
Training hall On/off
I agree with Juances it would be better that way.
Yeah a sparring room at the back of the training hall would be great.
Yup, i agree with Juances and Haematite too. But then, would you be able to die from taking damage? Players with proto sets might have to spam revive when someone starts swinging a DA/GF. How about four sparring areas where the first three are limited to tier, and the fourth would be a free for all? And you could also have damage numbers popping up outside the sparring area when players are attacked, but with no actual damage taken.
Have an option where the party option buttons is to turn PvP on/off. If you have it on, other players in the Training Hall can hurt you and you can hurt them. While you have it on, a red ring around your feet appears, or perhaps a marker above your head. Or possibly a flag like in Lockdown.
More like a spceial section where friendly fire is on when you enter would be better.