I don't think that the untouchable aspect of the b29 is going to be a big factor in the MA. Even for the perk points, who is going to spend and hour climbing that big bird up to 40k anyways? I hear plenty of people say that "who ever gets above 20,000 ft to bomb in the MA?" I don't think people will treat the b29 any different(after the cool and new aspect is over). And anything below 20k (where most MA bombing happens) the b29 is just another big four engine target.
Vudak is right, how is a 500 perk, no formation b29 going to do that much harm?
And just so it doesn't come up....I do not want to see the nuke.