Survivability says... package the radio in a tight group so there aren't long servo leads that can be hit and ripped out of the RX or servo. (those old 3 ch systems that had the RX, and 3 servos built into one case in the mid 1970's would be ideal on this issue. Just a battery lead.)

If you have a 3 inch lead beteen RX and servo a wing is eventually going to snag it. (usually meaning you had wing sawed off in the mid-air... but its a pain soldering back in a servo lead)

There will never be 100% protection fr any part of a combat plane... and excess armor is just weight to make you slow (and therefore a target)