I like the radar piece (and I think you defined it well), but, unless I am missing something, it seems to lend itself to helping a passive player. In other words, is there a better use of radar than putting it in the front or second row and using the aerial on Move 1 and leaving it there?
I think this game, as defined, is played optimally in a defensive posture and any modifications to the rules should be made to benefit the aggressor.
That said, I wouldn't mind seeing a radar piece added if other additions favorable to the attacker were made simultaneously.