Personally I think the TBM and B5N should both have a formation option because of the level bomb sight they have. Its not like having two drones would make those planes much more survivable and the extra fire power would encourage more use. However, the TBM and B5N were not really used in large formation level bombing like the B17, B24, Ju88, etc. Yes TBMs and B5Ns flew in formations but the entire formation didn't drop on the lead bombardier's command and this is what the drones in game are used to simulate. I think that is the main reason why we don't have formations for those birds.
If I am wrong, I'm sure there are plenty of guys that have been here longer who can chime in with the real reason.
