I can see the a1 could potentially give extra damage, and i do use michinaki in my nm hydra team.
However, she doesnt actually do a proper cleanse? so cant take the place of the person dealing with fear? . She reduces debuff duration by 1 but that still leaves a lot of fear in play. The passive just cleanses one ally
And she doesnt do a proper block buffs, just reduces the enemy buffs duration, so cant replace the solution you have in place for poison cloud / stolen buffs either.
And that is how the champ (base form) feels generally, like it 'almost' does a number of roles, but none of them as precisely as other champs do hydra roles.
I dare say people have incorporated her, but i dont see how i could.
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Having said that, my NM team is not great - it tops out at about 200 million damage for about 800 million points which i know is way below the big guns here. So would love to see how people are properly incorporating her and still keeping poison cloud / stolen buffs / fear not an issue (i dont have shammael and didnt have the voids for the event)