I personally feel that to take out just one single target and shut down an entire nations radar is, well...too simple.
I've read that others like radar and some here wish it was gone.
Would a radar chain enhance gameplay in any way? Each base has it's current radar...only base radar can be disabled, one at at time...effectively punching holes in a countries radar chain.
Missions could be flown plotted through these holes allowing for the element of suprise rather than the current early warning radar effect we have now.
Destruction of the city would still affect down time, and perhaps the destruction of the current HQ's could have some other affect...possibly disabling the strat data or other informational data due to the fact that HQ's are full of paper pushers

Just a thought...
Ice