The spell will be useful because it deals in damage types that are much harder/impossible to resist.
The spell won't be as universal as wall of fire for a variety of reasons. For leveling purposes (near-solely), the double-damage to undead factor of wall of fire is very important. AoE spells like wall happen to work the very best against some of the otherwise most-annoying monsters found in the leveling range past wall's availability (example: shadow crypt and its associated tombs).
For higher level play, it is pretty rare to find a perch and throw a firewall and let stuff bake in it. Standing still with aggro, no matter how good your healing or mitigation effects are, is a really good way to die quickly. Ice Storm has the advantage of a much larger area, which is good when moving around. However, wall has the advantage of "deals damage to enemies crossing over the wall". An experienced caster player can bring monsters back and forth through a wall of fire much more frequently than once every 2 seconds, which is a big part of the efficacy of wall of fire and its damage to mana ratio. I will find a way to get ice storm on my sorceror, but it will be the spell I use when wall doesn't work, and I cannot imagine to the moment a situation in which wall of fire presently does full damage that I would prefer an ice storm instead (unless ice storm itself is getting some kind of damage bonus).
However, there are tons of situations in which wall of fire would be breaking the game if monsters weren't immune. So the question remains whether ice storm, dealing much less damage but working on all those things (especially many raid bosses) will be a very good spell. My guess is that it will be. It won't be as ubiquitous, but with the present design of casters on DDO, it's nearly impossible for it to be: if a spell was as good as wall of fire but simply not fire, the game would break quickly because the only reason content works from levels 16-20 is fire immunity. If there was a lightning-elemental wall of fire, I'd never cast another damaging spell unless I was bored. So Ice Storm can't be that good. I think it'll take several months of play before we know if the present version does, or does not, provide a solid alternative for situations where wall of fire doesn't work.