Actually, I think all these (hints, sprays, voip) are manifestations of a deeper issue: the need for better communication/intelligence.
Currently the main type of communication is team chat, upon which individual players build by using binds or HUD aids to say stuff and issue taunts, and volunteering crucial information (base under attack etc.) This is arguably not very effective.
VoIP may supplement written chat to some extent. I say supplement rather than replace, because there's no voip substitute for split-second announcements via binds.
As things stand now, team coordination is purely a matter of luck and individual skill. People run around frantically with only minimal intelligence and some of them are in the right place at the right time with the right skills in order to make something happen. And sometimes they're not.
Pro clans, as I understand it, train a lot together and have standard formations and tactics which can be ordered at a moment's notice. That's better than just running around aimlessly, of course, but still not quite there.
And it's as far as things can go as long as Trem doesn't feature full game intelligence. By "full" I mean something like a 3d map representation of all the players, which a designated commander could see and guide his team accordingly. Trem features only limited radar, which is only available to individual players, which may choose to announce what they know or not.
If you want to get into this, for the sake of argument, I could propose the advancement of a new type of structure: the sensor. Zero (or very low) BP, no need for power/creep, and large area coverage.
And then there would be the question of how the sensor intel would be presented to the team. Would they all get a rendition of a mini-map on the screen? Or would the intel only be available to one player, the designated commander, who in turn would guide the team?