A PBY just barely has the ord capacity to sink a CV as they are modeled in the game, if everything hits dead on.
Any plane can be used in scout role. Ki-67's are good in search and destroy mode for carriers. Speed and good bomb load to kills CV's.
It might require a change or modification to water model, to allow landings and take offs from water. Especially the take offs w/o wrecking the plane, my guess.
Too many other planes with more usefulness toward the game as it exists now could be added before a Cat.
Want to fly a CAT? Get MS FS and download any of the PB-Y's out there for it. Some even modeled as water bombers, and I'm sure someone has written missions for it for the FS game.
If we were expecting an influx of lots of planes, PBY would be nice, but as planes come in a little at a time, ToD is getting lot's of attention, and rework of existing models also a priority, any new additions need to fill a wide range of player's wants, needs, goals, and objectives.
B-29. Pretty sure additional of a B-29 would necessitate a rework of the fields and many maps, as I'm not altogether sure that a loaded B-29 could lift from the current airstrips. Loaded they weighed over twice what a B-24 did. It's a big plane.
Then there is the increase of bomb capacity. 20K per plane. Last time a plane added with so much ord resulted in increase of size of towns to address it.
B-29 is high altitude bomber, operates where few fighters work well, or where few pilots will tend to patrol. As the game encourages combat, having buffs at 30+K defeats the purpose.
Then there would be the nook whines.
And it's been said many times.... no Superfortress in AHII.