Same nora, almost same damage, but one is AoE 3 and the other is AoE 2. I don't believe that 2DMG is worth as much as 1 AoE. Why is it still like this?
I could also compare two other spells: sheoul's fireball and crescendo. both 35 nora, both hit 3 champions. first one needs to kill a unit and can hit your own champions in range5+range5 and the second hits range3+range3. I dont believe range 5 is so superior that it needs two drawbacks.
Aoe spells need revising. They nerf everything that is overused (ice storm, stellar horizon) instead of balancing their damage and nora cost. Superiority is currently the best spell with its enormous aoe6 (!) and dealing quite damage for same nora cost as things like fireblast, acid storm, lightning storm, burning sands, stellar horizon.
Spells havnt been revised since the revamp unfortunatly. and due to their nature are always unbalanced due to their unpredictable nature by design. I.E casting an aoe ability such as poison cone on a champ is easier to negate as you can "see it". unfortunatly you dont know if a spell is drawn and so are left guessing, the fact that their effect is instant and in general have larger aoe's creates balance issues with numerous spells, most spells at the moment are largly undercosted. arguably the cone nerf to 3 cooldown made spells more ideal due to the things i mentioned above. add to that, that reclaim relic and other anti relic abilites have been splashed about here there and everywhere also encourages the use of more spells due to some relics now been overcosted due to effects like seism.
Because they are different factions and get different things. AoE spells are now apparently more SL's purview than UD's. Deal with it.
You can't compare two runes flat out like that, you have to look at the whole faction and how it plays together. If ice storm was removed from the game, would deep freeze get more play? probably If acid storm was removed, do they have any other decent aoe's? If fire blast was bigger, would superiority still get used? Some factions do more dmg, some factions have bigger spells, some have more damaging spells, others have pain in the ass relics, and IS has too much defense. nerf IS
I think this idea of universal formulas is actually an enemy of faction individuality. But who cares, it's how the game is now, lets play it.