Storm "makes sense" to me. It has higher base damage, is a damage type that practically noone is immune to and many are vulnerable to - lightning. That's incredibly important, and the reason why lightning damage is so sparse in the game. You can use it against any monster. Actually, that's probably the intent - against monsters the random nature of Storm goes away since you're mostly fighting just 1 enemy at a time. Yes, it takes 1 extra turn to cast, but factor in that you also get Haste from air1 which is a no-brainer to cast every fight.
Air2 will also get you Gentle rain with water2, or Contagion with death2 (two of the strongest spells in the mid-game).
The only thing I don't like about Storm is that it's air3. It is very weak for a spellrank 3 spell imho. I mean, we shouldn't even be comparing it to Flame Dart. We should be comparing it to spells like Fireball and Summon Ice Elemental.
I wouldn't care if Storm is an Air1 spell. I still wouldn't use it. Its random target plus casting time verses its damage or usefulness compared to the available alternatives is what kills it for me. If it were not random or it was back to instant cast, I would use it more. Even the random nature of it kills it for me as far too often, I've spent the resources to cast Storm only to have it strike for 30+ damage the guy with 2 hit points left while leaving my tank to die at the hands of the other bad guy that could have been dropped by a Flame Dart or two before my tank died. The only time I'd even consider casting Storm is against one of the uber Wildlands mobs like Morian and if it isn't doing AT LEAST double the damage of Flame Dart, I still probably won't use it. I'd rather they double the mana cost and make it instant again.
Combat is so fast in Elemental that ANY tactical spell that takes longer to cast than Instant will get very little use. Combat moves too quickly and is over too quickly. What it takes to get a caster with high enough initiative to make Fireball useful pretty much breaks the game. Nothing sucks worse than passing up the opportunity to cast THREE combat spell only to have Fireball go off and kill or just damage only one or two bad guys. And once you start casting a multiple turn spell, you're stuck casting it. If one of your guys is in danger of dying and all he needs is his opponent nuked or a quick heal, he's screwed because your caster is tied up trying to cast a spell that might be useless by the time it goes off. If they feel a spell is overpowered then they need to leave casting time alone and increase either its spell level or mana cost (or both) and/or cut it's effectiveness but they need to leave casting time alone.
Same with Fireball. It's only useful *IF* you're up against a bunch of big stacks of trained units AND if the trained units are packed closely together (in the last patch or two the bad guys are spacing out more at the start of combat) AND are pretty sure you can get it off before the bad guys scatter all over the tactical map. When those conditions are met, it is a DEVISTATING spell. And when you get to the point where those conditions are met, then you're nuking the bad guys to ashes in the first 20 seconds of every battle and watching the excitement of the game degenerate into a snoozer because then it is WAY TOO powerful.
Fireball in its current form(except for casting time) is a huge mistake. AOE plus Overpower is so devastating against stacks of trained units they've nerfed it into uselessness rather than addressing what is really the problem with the spell. I think they need to change Fireball to a range-zero spell with Overpower, and possibly change Overpower to be (Damage * 1/2 Target Units) and change it back to an instant spell. You'll only be nuking one mob/stack at a time but against a group of trained units, it's devastating without taking out the entire army of bad guys with a nuke or two. But keeping it an AOE spell and taking away Overpower would also be a reasonable option if they reduce the casting time to instant. Actually, I'd keep Fireball AOE and get rid of Overpower then come up with a different spell that is an "Overpowered" version of Flame Dart. Then you end up with two spells that are actually useful without either being ridiculously overpowered or near totally useless with nothing in between.
Similar thing with Titan's breath. I have sacrifice two casting opportunities to cast a spell that might accomplish nothing if the better part of the bad guys are immune to being knocked prone. It's pretty much useless against any four-legged bad guy from the start. Throw in the 50+% likelihood that the most dangerous of your opponents are probably immune to being knocked prone, on top of the two turns to cast, and it becomes a very big gamble to cast. No thanks, I'll take my chances with Two flame Darts or Haste and Stoneskin. Chances are, any bad guy so powerful that Stoneskin and Haste on my main tank won't be enough to swing the battle in my favor is going to be immune to being knocked prone anyway. Spending one turn to cast Titan's Breath might be a worthwhile gamble. Two turns is not.
Like I said, I have very little use for any tactical spell that isn't Instant. Tying up my main caster for two or three turns to cast a spell that might end up being a waste by the time it goes off is not in my nature to use if I have ANY reasonable alternative.
Sorry for the rant. 
