Bomber gameplay is already full of too many concessions.
True.
However, lets consider the gameplay for level bombers. There are two ways to go: High, above the fighters at least till you get to the drop. Low, fighting the fighters off with your guns. Since the mossie XVI has no guns and low altitude speed is good but not enough (not to mention attack from above), the second option will be difficult without good friendly cover. Coming in fast and high is much more likely to get the mosquito to the drop, but putting a bomb on target from 25K while going 400 MPH is not an easy task - even with the easy mode calibration.
What will formations do? For the low altitude options it robs the B-moss of its only defense - you cannot maneuver to evade attacks with a formation without loosing it. A players who cares not about his score can abuse this by taking the drones as "extras" and let them die if he is attacked (giving free two kills to the attacker?). Even a perk tag of 1 will seriously lower the number of such cases. For bombing accuracy, this helps a little. All 3 cookies will drop together, but will cover a wider pattern of total destruction - this is a waste. many small bombs are more effective for a city and the spacing between the cookies is not enough to take more than 1 hangar with an overkill. The new CV killer?
So the only thing formations will add to the B-moss is increased effectiveness as a daytime, high alt level bomber - something it was never intended to do in real life, but the way it will play in AH. Unless coming with heavy fighter cover, a low/mid-alt level bombing is better served by a bloated 4 engine machine. Enabling formations, with a small perk tag will allow it to be an effective high alt bomber, prevent/minimize miss-use and give something to spend the easy-to-get but useless bomber perks on.