ArduSub Rx Support

Hello, I understand that ArduSub does not support receivers and that receivers do not work under water. ArduSub has been developed primarily for ROVs. However, various posts over the past few years are from people (like me) looking for something that can autonomously conduct a mapping mission without necessarily wanting live streaming video or manual controls beyond activating the mission.
Is there a case for ArduSub supporting a Rx receiver mounted within a small streamlined buoy, towed behind the AUV on the surface? The buoy would also contain the gps receiver to provide an offset position to the Pixhawk. The UAV could be equipped with sonar for maintaining a set distance off the bottom similar to terrain following on arducopter.
What would it take to add Rx support to ArduSub or alternatively should we considering Arduboat instead and adapting for subsurface operations? Really keen to hear what other think.

I think you might have issues getting the signal from the receiver on the buoy to the vehicle down below. You may put a router on the buoy instead and connect to QGC + joystick, as is the intended use case.

ArduSub is for submersible vehicles, arduboat is for surface vehciles.

Yes, you make a good point. For depths >20-30m getting the GPS signal to the Pixhawk could be an issue. Even though we are only going to 30m max, it may be worth going to a bigger buoy with a router on board even if it is harder to tow. Thanks for your feedback.