There currently is no real impetus to go to fullscale UAV
deployment because the solution we have works well
enough already. NATO manned airforces are capable of
closing down the air-defense networks of any likely feasible
enemy without significant combat losses. If the cold war
was still rolling this would not be the case.
I personally believe that an actively funded UAV program
with todays technology could create aircraft that would be superior in combat to conventional air forces.
However there is always a lot of investment in status
quo, so I don't see NATO doing this overnight. However
a small country which was willing to take a chance on
new technology might well be able to field systems which
could beat a more conventionally equipped opponent.
The places where I would look to see this happening would
be say, India-Pakistan, China-Taiwan.
-- Andrew