The comparison between Iceheart and the other two sets (Phoenix and imperium) is illogical for several reasons.
1) Iceheart is a monster set. Monster set bonuses are not and should not be held to the same balancing standard as 5 PC sets.
2) No one uses those sets. Now no one will use iceheart.
I get it, you made a new monster set and it was terrible. But what do you think the best course of action should be? Nerf a set that is being used and is fun in casual play, while not buffing the garbage sets? Or maybe dont nerf the fun set, and try to bring other sets closer to its level so players will use MORE sets in the game.
Your balancing decisions are so terrible I'm furious. Maybe if you thought iceheart was too good, you could try a small nerf, like nerf the shield strength down to 7k or 6k. It would still be a good set with CP. What you did GUARANTEES no one will use it.
Is that what you want? One more set no one will use. You guys are really in charge of design? Damn that's scary.