Current game, fire/ice is supperior. Honestly, nothing can beat a proper firewall, and as a caster, soon enough you'll figure that out. But if you really think your play style is better, nothing is stopping you from respec'ing.
Not to mention, polar ray (cold) has no save, firewall (fire) has no save, scorching ray (fire) has no save and stuff usually isnt alive long enough for acid to be usefull.
Now, soon they are actually fixing chain lightining, and it will be god, but still nothing compaires to max/emp/etended crit firewall for 400-600 dmg a tick for a solid minute long (or soemthing like that, but close)
Cool thing is, is nothing is stopping you to havning both