Alright. So lets start from scratch. (And if even this can't be balanced, we'll see how far the rabbit hole goes), what
should each element's "thing" be.
Regardless of how effective it is.
Immortality - Perfect as is.
Airborne. - IMO needs work. Throw in more evasion. Re-nerf fog's percentage, but have it also apply to spells targeting airborne creatures.
Theivary/trickery- Pretty good, but not perfect. It just needs a bit stronger late game. Shadow Beast: The enemy sees a TU. You see a copy with 1 HP.
Decay - Perfect as is. I wouldn't say no to the tiniest of buffs to vulture.
Burrow? - I like the half damage vs. double damage dichotomy, and it's close. Tunnels: Burrowed creatures get momentum.
Chaos. Randomness. Luck. This is probably the closest non-perfect element out there. If it had some sort of reverting method to get the base creature out of a mutation, it'd be perfect.
Destruction. - Disagree if you like, but this is the strongest element in the game.
Inevitability. Two fixes. A QoL buff on charger so the momentum is an activated ability. More gravity pull synergy. Next, armaggio also pulls spells. Soft protection
Evolution - Best synergies in the game. Just stop nerfing it! Adrenaline/devourers isn't OP! SoR/mitosis is still slow! Maybe SoR/rustler infinite mana is broken, but the duo was completely slaughtered!
Ferocity - Rush creatures, and rush them fast. Give it a spell like cremation, and watch it dominate like it should.
Give it a pump spell. Holy life deals 2 per 10, or heals 2 per ten. It's basically a worse version of drain life OH WAIT IT'S A PUMP SPELL IN LIGHT.
Draw power - Give it a card that gets stronger with extra draws, and a card that supports rainbows
Flexibility - A SoR clone didn't work, maybe make liquify a global effect? All creature's active abilities are free? OR! Buff flooding so water creatures can use their abilities for free!
Just my ideas.