Technically, there is a lot of bandwidth required to send information back from the unmanned combat vehicle to the pilot on the ground. And there's a problem that you need to be able to send control inputs to the combat vehicle in real time, without risking interruption from the bad guys (either your enemy forces or a bunch of bored chavs on a council estate).
For a UAV with no (or v. limited) combat capability, you can get away with sending less information back, but in a combat situation (whether dog-fighting or ground attack), you need a fair amount of info to maintain situational awareness. This can be video feed of some kind, as well as radar and other sensor feedback -- updated in real time.
What can you do in designing such a system?
One choice is to give the unmanned combat vehicle more autonomy, via smarter computers/skillful programming (shameless plug), so the beast can make some decisions on it's own. Downside of this is obvious -- the damned unmanned combat vehicle might start shooting at the wrong target (which is clearly not a problem with human pilots
)
Another thought is to tie the pilot's workstation (OK, we'll call it a 'cockpit' if you want) in to other "god's eye view" systems as well as data from other sources. Then you can minimize the data needed from the unmanned combat vehicle, as well as adding some significant computing power on the ground to present the tactically useful information coherently.
Real advantages of an unmanned system:
(a) airframe can be made to survive more extreme G-forces
(b) don't need to carry "life-support" or indeed human-readable cockpit displays
(c) if it all goes horribly wrong, air vehicle can be blown up or steered into the ground at great speed without having to worry about a pilot getting out.