Suggestion: A new module that works like the science department or CIC, which can be staffed by a ground unit commander, and can act as the highest level hq for a ground formation. Eisenhower didn't go ashore in the first wave on D-Day after all, but that's what happens in Aurora.
In order to work like I think you want it you would have to break the requirement for HQ's to be in the same location as the ground units in order to provide a bonus.
And if that's the case, why not have Eisenhower back on earth instead?
The flaw with your analogy is that when attacking a planet you can land literally anywhere on the planet, so all you do is locate the defenders, land your assault divisions 50 miles away, land your support divisions 100 miles away, and your rear area units 150 miles away (distances representative, not literal).
No one gets shot as soon as they get out the transport and everyone has time to get in formation for the big push.
Whereas Eisenhower was limited to a narrow strip of French coastline (unless he wanted to join the paratroopers).