Even without collision avoidance being available, it would be REALLY nice if the RTH function would allow height adjustment. IE: In the area I fly, there are numerous objects higher than 30ft (default altitude for RTH) around me. So in the event of lost signal, or some other scenario that would involve the function being activated, the drone would raise up to a safe height (In my case it would be 60ft) and come back to me without any objects in it's path.
I would think adding this feature/option would be a matter of a firmware update.