Lets pretend its in the 1940's, and you get a 21 century network centric all-seeing radar (read year 2029 with satellites and high flying AWACS ) that can see all of the battlefield, even behind mountains.
Now you cant hide, get altitude without being jumped, you cant fly in behind an attacking force unnoticed and create some havoc - even outnumbered (like it used to be).
You can even rely on an radar that tells you where the enemy is if you lost sight of the enemy in a dogfight - currently - not like it should be in a wwII sim (and like it used to be).
is there an issue with radar? I've not noticed.