Oh I beg to differ with Siegfried, I never use him ever since I found out what he does. Just doesn't fit my play style. But each to theirbown of course.
Atm, I prefer playing United States than any of the other Allied factions, because of their fast speed, quick strikes, and air supremacy (Warhawks are easily one of the best Allied support and defensive units, as their lasers are quite damaging against infantry and tank groups). I do like playing Alliance time to time though.
Hailstorms used to sorta fill in the anti infantry role when blizzards were relatively subpar, now they can't exactly do much since their damage for structures is just pathetic, not to mention the fact it's far too sluggish of a unit to be a worthwhile pairing with the current zephyr/blizzard unit comp.
They definitely do need a buff that would allow them to do actual siege because right now no one is going to want to waste time making a sufficient amount of hailstorms just to tear down some buildings when they can just inflate the numbers of zephyrs and blizzards and get an even better outcome.