[Shujin]

Well I mean...While I agree that some formations really are kinda useless, like arcance formations invocation break part (Since you usually have 100%unbreakable anyway). In case of frigid formation the best ones are Bunker and Attack since those are the only ones you can actually move and place.
Bunker technically being the best cause its a straight line, meaning when you move in to attack after, you atleast get some benefit from it, the triangle of attack formation is...weird for that matter, still good to atleast get frigid formation of in the first place. Volley works when they stand directly next to you, and arcance...Basically unuseable for this,or rather in very specific cases.

But even if placement wasn't a problem, a double tap of any other spell is flatout stronger(and usually has a status effect aswell). So even then, it still needs a buff of sorts in the form of a staus effect that makes it a bit more interesting, preferably.

How about something fancy as it's effect:

If an enemy is on your formation tile, he absorbs also range=rank ice tiles around them (circle) and increases the damage it deals by Ice tiles consumed %

If ally stands on your formation tile they absorb range=rank ice tiles around them and grand them a armor level ice tiles consumed*2, that reduces it's level per damage received (See Jarmor effect)

That way it has the special OOMPH when it has been set up probably and if you have partners, it can also be used as an assistance spell, instead of just an offensive. Besides I like the idea of actually using ice tiles for stuff. Just a random thought that popped up. Probably still not the right way to go about it, cause the set up for this is....Way too much.