Solaris' last ability, which charges when her allies are hit instead of having a cooldown, is my new favorite ability in game. Not just because of what it does, but because of how it's used. I want to see more heroes with these kinds of "charge" or "fury" abilities. Perhaps Ekko's Energize could be on a charge rather than a cooldown (but start charged), and would gain charge whenever any ally hits a Shocked enemy.
I think these types of abilities should be like ultimates in League or Smite or Overwatch, just like Solaris'. They should charge in some unconventional way, but also be extremely powerful, just like Solaris'. Perhaps every legendary could have such an ability.
IGOROK's Taunt could be moved to his second ability, replacing Arctic Rush. Then, his last ability could be called Arctic Annihilation - a move that charges a small amount whenever IGOROK or a Water ally damages an enemy. When fully charged, he would attack a single enemy for (200% Attack) Melee damage, apply Boss Frostbite, purge all buffs, and deal 1.75x damage if they were Chilled or Frozen.
What do you guys think? Should new heroes also have these charge abilities? Should older heroes be reworked to have them? I personally would be sad if Solaris was the only hero ever to have such an ability.