Ice blast has a shorter range than ice shard, fire bolt, and firestorm, putting you in aoe range to cast it.
OTM had ice blast right when they first released it but nerfed it by 45% for some odd reason. I think low level castle dwellers made a stink about ice mages in pvp so OTM severely reduced dps for ice mages. 10% reduction for ice shards and 45% for ice blast, all on the same day.. It is in the patch notes if you want to look it up.
From the patch on 15/05/2013:
Mage:
Decreased energy cost of Ice Blast by 10%
Decreased power of Ice Blast by 45%
Decreased power of Ice Shards by 10%
Decreased power of Firestorm by 20%
Decreased power of Incinerate by 10%
Decreased power of Energy Shield by 25%
Increased recast time of Firestorm by 5 seconds
http://celtic-heroes.com/patch-15052013/
In the end, mage is the least played class in this game. It wont change anytime soon. Rogue is currently the most popular class.
Here's a comparison of Fire and Ice:
Take that damage, and multiply it by 25% which will be your damage on a dl boss on average because of the 2k+ resist. Then factor in a 20-30% evade rate.
Lvl 191 Mage, to lazy to level past that.
Lvl 150 Druid
Rhiannon