If Blizzard crits often and if stun procs from magic weapon: electrify, then this could be a pleasantly different kind of mid-to-late-game build. Comet would be the "nuke" that leaves a slow / damage patch in place, after it is dropped; if the ice patch left behind after comet drops can also crit and proc stuns, then this build becomes even more mechanically effective.
Comet becomes the opener for most situations, with Blizzard cast shortly before Comet arrives; Blizzard can be used through doorways and for scouting ahead, as well.
The lack of a signature spell means that AP management would be key. Kiting would be relatively easy for most mobs, but "fast" champs and boss packs would admittedly be awkward.