Playing a character who will eventually go into Arcane Trickster and came across this spell...wondering if I'm missing something.
From my understanding if the original shot qualifies for sneak attack and kills the target, next turn I could cast Arrow Eruption and each of the arrows that come out would apply sneak attack damage to their targets. Am I missing anything?
The rules of sneak attack prevent the extra damage if the other opponents aren't denied their dex, aren't flat-footed, etc otherwise, yes, they take sneak attack damage.
Not sure that I agree a RaW reading of the whole thing ends with Sneak Attack over riding the mechanics of the spell, but that's likely how I'd rule it as a GM.
Glad to see I'm not missing anything though. All in all it's situational, but I think it'll be pretty effective in those situations (and I imagine those situations wont be terribly rare in the game with this particular character)