It would be really valuable to have some type of notifications to an admin for received text messages. This could be as simple as a daily email summary to a designated campaign admin for unadressed messages. This would help prevent messages from falling through the cracks.
If the manager or the admin makes an agent account they can set it so they can see and reply to all text messages not just the caller. I do this, and will periodically check the texts throughout the shift, as well as in the morning so I can reply if need be. This is really handy if you don't have the same callers every day.