Overall i'm liking what i'm seeing so far with Kali, with the exception of 2 things:
1. Her Ult is binding. The problem with this is that it's useless when her oathsworn is not around and leaves her very vulnerable in clutch situations mid and late game. I think it would be better if was not binding, and became usable for any champ on her team... If you did that, you can remove or lower the max health damage on soul-marked to balance it out.
2. Her power level . After infinity edge or statik shiv, she's just so monstrous. The max health chunking just snowballs it.
Anywhoo, those are just my thoughts :)