As to movement, MP is very abstract, but its a lot easier to track vs actualy having to know where your dropships are at any given moment. If I was back in Clan Mongoose and I only had seven clusters, or even the Mandrills with about 20, it might be doable. But even the CC with only ten regements and eight warrior houses, I could never hope to keep up. Granted, I don't have to, because its yours Fate to do, but I won't wish it on anyone.
Then again, I have long argued that incomming our out going ground troops should be able to fight. As is, they just lose automaticly even against the small forces we tend to see in this era. But, a squadron of fighters shouldn't really be able to hold up a flotilla of dropships. A regement using Union class ships would outnumber a squadron of fighters by 50%, after all, and even against a wing they could pit each of their dropships against just two fighters. So, the idea that a 2-3FP wing of fighters should be able to keep a 20-30 FP RCT riding in two dozen dropships from a planet is silly.
There should be able to be a fight. That said, yes, if there were two or three wings, or if there was a warship, it should be a slaughter, absolultly. But, even still there would be risks. And if there were just a few system patrolls, it should be a risk, or even a slaughter the other way.
I don't know what sort of system that calls for. I've proposed assigning ground units 1/4th is FP in space for each of their ground FP, which seemed reasonable to me at the time based on common dropship types. I think that gives players more options. Sure, maybe you can smash through that defending fighter wing, but if it can kill just .5FP of your space combat value, then that's 2 lost ground FP. Is that worth it?
And, as I've said, I still think most players will just continue to send their own air units in to sheppard their ground units down, as is done in canon anyway, and this rule will nearly never be used. But, I've never liked the way that ground units were basicly impotent in space, despite having massive numbers of dropships avalable to them.