Dragons have since begining of KB been sick units, and in CW with proper items thay are even more ridiculous (ancient ring , hearth of dragon, draconix, and voice of dragon skill 3rd lvl).
But my question here is this : Why paladins ??? Rune mage i get for resurecting, demonologist for meat shields (both this units are great for mage hero with archmage skill), but paladins cant second wind dragons, or resurrect them, so i wonde how do they help in battles ? Low speed, to high lds requirement for mage to stack them up...
Better bring Emerald dragons instead if you have some of items i mentioned. They are great for building trap medal, and generating huge amounts of mana with their skill.
As for healing black dragons use gizmo spell, it owrks on them, but it`s uncontrolable
Best chanse to heal them, is to cast gizmo on free arena lsot next to them instead enemy unit.