Really not a big deal. Boba it kind of killed because he's already pretty squishy but when he revives all his debuffs are gone. Kylo can inflict healing immunity on his basic and is tanky enough to survive a turn without the protection gain. Can't speak to dooku but with new sith meta he too should be fine.
There are really not a lot of teams I come across who run characters with healing immunity to begin with. Either way, everything should have some kind of a counter. Put a tank in your line up and problem solved.
I feel worse for those who zetad savage in a zmaul lead thinking it would be a game changer. Savage can be good, if all the new sith were around him, but terrible otherwise
