I admit that Lancasters are not too difficult to take down with some patience. And I agree that a formation of 3 17's can be killed, But the fact remains they still seem to be a little too lethal. Reducing survivability may make for better game play. For those that like to drop bombs, one less drone would not reduce their fun but survivability would go down. This in turn may result in more strategy because a B-17 may actually need escort. I think it would reduce the milk runs because escorts would mean a bigger dar bar and attract more attention.
I, for one, see this as an improvement to strategy.