Water
This element has everything:
Poison
Rush
Creature Control (Ice Lance, Congeal, Mind Flayer, Arctic Squid, Flooding)
Permanent Control (Trident)
Defense (Permafrost Shield)
Healing (Purify)
Did I forget something?
You forgot a few things.
-Drawing power (precognition and Hourglasses)
-Other forms of Quanta gain (Rays of Light, Leaf Dragons, Devourers, Immolation, Nova, etc.)
-Stat Buffs (Heavy Armor, Blessing, Momentum, Adrenaline)
Although I have to say, you're right about
suddenly being one of the most versatile elements in the game now. It's because of all those crazy new changes/implemented cards now...