Well, as you suggest, making it a two man job, people would just say "get two goonies and go in at different angles > get a goonie and a glider and get shot down together".
If it were a one man job, with a goonie tugging a glider, then its a matter of u carrying 2x the troops, which HTC rightly disapproves.
Only way I can see this 'ever' being useful is if any light/medium bombers could tug a glider along, but Im not sure if any ever did.