I specced into shatter so that every once in a while I might get some sort of controlled burst and perhaps a controlled hot streak proc for once... but in Blizzard's continued infinite wisdom they made it so Living Bomb ticks are affected by shatter and now a single LB DoT tick breaks Frost Nova 100% of the time - literally - ruining not only the ability to utilize the talent, but utilize Frost Nova in any meaningful way.
As a fire mage I have to diligently keep LBs up on as many targets as possible, pray for a few casted crits & a proc, while trying to survive in my toilet-paper suit. Whereas shatter could be a boost to the #1 fire issue; crit RNG / uncontrollable burst... it actually backfires making frost nova less useful. Toss us a PvP bone and let us make use of shatter rather than penalizing us for doing our job with LBs - breaking every frost nova in sight.
Note: Making this change would do absolutely nothing to benefit Frost Mages.
P.S. - If you're feeling generous, consider removing the Firestarter penalty. This penalty has meant that the crit reduction buff will never be utilized by anyone ever again; it is now a vestigial buff.