this is exactly the solution I came up with, however with a caveat. I wanted turn two to have 20% change to die, and 20% chance to fall off. In other words you can react, but turn 2 is just as likely as before to kill a troop.
I'm fine with it though. I cant tell you how frustrating it is to get hit by an entangled wraith (4x skulls) for one damage and have the troop instantly killed (gorgoltha had full mana) before you can do anything at all. Its not good for the game overall. Cleansers should be able to counter death mark.
SIDE NOTE: could we please make poison 100% chance to deal damage each turn? Its already a joke status, this would actually make it usable imo.