Have the ability for a Prof to talk over grouped headsets or the whole lab.
This would be a nice faeture, but would take a lot more work to integrate VoIP
They are creating a CDS, so that is something that looks a lot more possible now.
Until Springboard puts in this feature, I would suggest using Discord. One of the nifty features it has is you can set priority on certain users, so that when they speak, everyone else gets quieter.