I thought of this when I was looking through Battlefleet Gothic last week. The gist of the Orbital Support for
40K idea is that players have one Orbital Support slot in their
FOC, and Orbital Support (shortened to OS onwards) provide players with some extra buffs (An example would be a Space Marine player having a Battle Barge in their OS slot, and this allows them to drop an Orbital Bombardment regardless if they have a Chapter Master or not).
A limitation I had in mind would be that you'd need to field a fleet commander or equivalent on the actual battlefield (ex: the Master of the Fleet for Guardsmen) and you only get one OS unit. Also, OS units would not be entirely pie plate dropping, but improving your Reserve Rolls, Twin-Linking artillery units, re-rolling Deep Strike, etc.
Feel free to comment and I'd like to hear feedback on this idea.