It is not unusual for an agent to 'forget' to log out of their phone when going off-shift which then causes a problem for the next agent wanting to use that desk. At present that problem is difficult to fix (you need the first agent's password to log them off and you need to go to that desk to do it).
It would be a MASSIVE advantage if we could see from the web interface which extensions are logged into which stations and if necessary log them out.
I know Asterisk keeps this information internally in it's database (I did once build something similar for a proprietary callcentre system), it's a question of how to access, present and modify it from the web interface.
All in, a highly desirable feature that isn't present on any other free system I'm aware of.