It'd be interesting. You could have a 'default' version that shows rally points and other players and does nothing else, that all players would start with. And a 'Command' version that shows enemies, players, and items and can actually SET the rally points. Of course, you'd have to buy the Command version (Maybe make it take 0 space, though!). Also, the rally points could be ones such as 'Move To', 'Weld', or 'Hold area' ones, so you can indicate what you want to actually do with that doorway you pointed (Just hold it, don't weld it, moron! Half the team is still outside!).
It'd be cool if a certain weaker class that's supposed to be all about information (*Cough*Commando*Cough*) got the 'Command' version for free. It'd give them a new role: Setting up rally points and spotting ammo/items for the team!