well, i think perhaps you haven't put it in perspective if you're saying this. a 300k AOSB is 7.5 Meltdowns hitting for max damage every cast. 7.5 turns is a long time.
i'm hitting Mist Dragon for at least 200,000 with that finishing AOSB, and have capped out at 299,997 with a slightly slower strategy. Mist Dragon's total HP is 544,405. so yeah, one AOSB cast is potentially 55% of her life bar.
pretty nutty in the current meta, tho like OSBs before them, i'm sure they'll soon be powercrept away due to lack of utility to go along with the straight damage. if you're going to use your AOSBs, now is the time.