I think Krampus is the better tank but I am missing a good red flank for him because BK is not fitting in this case: both have taunt and their attack buffs override each other.
Other possible heroes I have in my rooster are
Lianna +19
Magni +18
Ariel +10
Domitia +9
Elena +1
Vivica Costume (Cleric Emblems are with Ariel, Hansel and Rigard)
Justice
Leonidas
Noor
Azlar
I could strip Magni for Elena or BK for Azla but have the feeling I would rather weaken my defense with that despite Krampus as tank.
I don’t think putting Krampus at tank is worth all the switching you’ll be doing. I am certain your current defense keeps you in diamond…seems like a lot for perhaps a small improvement. That said, I’d still ascend Kramp for depth…he’s that good.
I think this defense is weak to a blue stack, even a green one. Sonya can punish hard your BK and Aegir and green has lot of dispel options too. I feel that defense is a little bit passive, though its a matter of playstyles.
Regarding Krampus. I think he could make a better job than Aegir on offense and in a hypotetic defense team.
I would keep that defense but i would swap aegir for Magni