You call it uncontrollable damagewhoring machines, but lets be frank. Your job as a damage dealer is to deal damage. As much as possible while still keeping up with mechanics. For this reason that mediocre dot (which is actually quite a bit of damage during sustained aoe) is the better talent.
I could see Storm Bolt on Siegecrafter belt, but Bloodbath should be up every time anyways and the weapon should be alive for the full duration.
Really I can't think of any fight in which Storm Bolt would be better than Bloodbath for Arms.