Chaos bolt permanently deletes the character it lands on. In addition to that it is now instant, costs no resources, has no cooldown and can be used in combination with fire and brimstone.
Is that overpowered enough?
Shamans get totems to summon each of the Elemental Lords (including dead/MIA ones), can drop all totems at the same time, no CD. Totems cannot be targeted or destroyed, elemental lords summoned by them last until dismissed, multiple totems of the same school can be dropped simultaneously.
Elemental Lords do what Elemental Lords do when summoned, fuck shit up. Destroy entire BGs, terrain, structures, players, everything.
Edit: Didn't go crazy enough on this idea. Added stuff.
Shamans get Volcano spell, that is insta cast, summons a huge volcano to surround the target dealing 5,000,000 lava dmg a sec for 5 secs then erupting for another 20 billion lava dmg. Also stuns the target while they are inside the volcano. Lava dmg is basically a less evil for of fel dmg, or w/e chaos bolt does.
druids get summon moon. It summons a moon to smash the target with a moon. does 50 hundred million damage. ignores armor, since you are being crushed under a moon.
Warlocks. Heartstone. Summons a healthstone inside targets heart, insta killing them, no cd, insta cast. 5 mana. also steals one ability from a target permanently. So after a while gives warlocks access to every spell or ability in the game.
Unlimited range on Death Grip. You can target someone in SW from Panderia and grip them across the world. Also, if the death grip misses then the target automatically dies, and their armor is destroyed and unrepairable, and they have perma rez sickness and must also become a gnome (unless they are already a gnome, then they must become a basic fire.)