From what I saw in the interview on Wargammer this is going to be a net=zero math equation.
We're getting 4 ship bomber formations per player.
We're ALSO getting target changes and bombsight changes that make bombing harder.
So the result is the same as we had before. A bomber pilot with his 3 AI buddies won't be destroying the whole countryside.
I really do hope that the bombsite is changed so that the pilot has some controls to fiddle with. At the very least he should lose the ability to zoom in. Bomb dispersion will probably be a small sideways movement that over the time of the bomb's fall will be magnified (the higher you are, the less accurate you are). Things like this is why having 4 bombers is not going to make bombers a huge threat all of a sudden.