Except that kill would not have happened with that carrier having support (like a fax).
I think the problem with heavy bombers is making sure they do not fullfil a role already filled by other ships, but better.
So stealth? I would say give it the Endurance Role Bonus:
50% reduction in Cloaking Devices CPU requirement
• Cloak reactivation delay and targeting delay reduced to 5 seconds
• No penalty to ship max velocity when using Cloaking Devices
You do not have the ability to covops bridge them around and make bombers obsolete, but you also can park them somewhere until it is time to do your bombing run in fights.
Then we have the next problem: Size.
The suggested destroyer size would let you move them very easy through wormholes (even small whs), also gives them quick gate travel.
Again, we already got bombers for that and judging from zkill they work just fine at getting rid of caps/rorquals.
So here is my take on this: If we want heavy bombers, make them heavy. Battleship size and mass.
Now for other stuff that would make them unique, without replacing other ships:
Role Bonus:
200% Bonus to Bomb flight time (which means you are quite far away from the target you are hitting, subcaps have enough time to react, like using a command destroyer to get to you)
Bonus to Bomb EHP, Explosion Radius.
Basically make sure the bombs are possible to avoid with small ships, but hurt a lot if you react too slow (or are in a capital/sitting still)
I am not quite sure about the slot layout, since Battleship size would suggest more slots, but there are exeptions for big specialized ships with less slots (Freighters, Bowheads)