Here is a thought on the matter of Radar.
Consider that it is a weapon breakthrough…that means it won’t be in every game of axis. I would suggest it would rarely come into play considering there are 5 other outcomes on its chart and tech rolls are no longer saved OOB. Even if you get a power a round, it might still take 3-6 rounds to acquire it and have an impact. Of course, your opponent could get lucky.
Also consider that it costs your opponent some IPCs to acquire it. If they spend too much researching it, its almost like extra bombing done, since they were not buying pieces to use on the board.
So, unless your opponent gets the breakthrough cheaply…5-15 IPCs and early; you will likely gain an advantage in pieces on the board, and in forward positions. I would rather spend 20 IPCs for 2 fighters to defend one complex and focus my air power and builds there.
I have to wonder how hard it would be to raid all of the factories that Germany can use, if they captured France and Normandy. If they bomb one, you can always build out of the other. Unless you have large bomber forces hitting each factory, I do not see how bombing is superior to transports and land units. It just takes too long to have a strangling effect: Time to build the bombers, deploy them, and build up damage on multiple factories…What would you say, 5-7 rounds of play before Germany is “forced” to pay for some repairs.
In closing, if you are a big fan of a Bombing strategy. The radar technology should not normally impact your plans, unless your opponent is lucky enough to get it early and cheaply in those select few games that this occurs. If I were bombing someone, I would want them to spend more money on rolls, its effectively extra “bombing” unless they get that 1/6 radar breakthrough, after getting their first 1/6 for the breakthrough. In effect, Radar does not break the game by removing or discouraging a strategy, as it is not a sure thing. Those games where they get it, are like those games when you lose multiple first round battles that you were counting on…every now and then, you just lose to die rolls.(assumes you can not change your plans mid game, which you could with a large bomber force)