The thing about the B-29 is it would allow us to use up some bomber perks. However, it would be perked so heavily that after a while (probably until we ran out of bomber perks, or the novelty wore off), you'd rarely see it in the arenas any more - which would sort of negate the point of adding it...
I'm afraid I still think the A-26 should be added next, just to fulfil the role of a perked bomber.