I'm getting a lot of complains about them. I am of the opinion that they are overpowered, at least in early game raiding, far less so later in the game. I see a few options for dealing with this:
First, take away bomber radar and put it on the air scout. Raiding with bombers becomes more difficult because you need a scout first, but it's still possible and the bomber is not weakened in its other functions and stay just as viable later in the game. This is the preferred option.
Second, require bomber to use energy to run its radar. Probably -10. This will require an extra pgen for standard 2 fast bomber build orders.
Other options include increasing cost/build time but I don't consider this to be useful.
Additionally, I'm going to mess with bomber to make them drop more reliably as in the community bugfix patch, but also will lower their RoF so it's harder to drop many times in the same pass.