Honestly the idea of Perk bombers as a parallel to perk fighters or tanks is a bit of a stretch to me. The Ardo is a good example. In what way is this supperior to a B26? No target that it can kill is worth the sortie, if the kind of airsupperiority that dictated its introduction exists in AH people just log.
There are few planes that accomplish much more. The B29 of course. But other than that what is a perk bomber?
Here are some ideas about benifits that a bomber might get as a perk instead of access to a better plane.
Armements.
The Grand Slam, Tall Boy, cluster bombs, anti ship missle, window, air launch v1s?
Exotic versions
The xb40 comes to mind.
I guess most of the problem is that compared to most of what the war was fought with, the B26 and the B17G and the Lanc are allready perk planes.
Other then the B29 you pretty much have to go to prototypes to get any improvement. The Ardo is just novel in my opinion and not unballanceing in any way.
Maybe the Perk fighters will make the perk bombers worth while. Fighters that pack 4 hispanos and can be flying 450 mph at 32k 7 minites after take off will definatly make a case for the Ardo.
I think window would be a very cool load out. drop a red dot on the enemys dar and or increase their dar bar for that sector...