Talk:Flame Tempest (5e Feat)
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It was basically, "1d8 per attack." This was on average an extra 4.5 damage per turn for anyone, or 9 damage for anyone who uses two-weapon fighting. An optimized build at 1st level can do an average of 13 damage (reference)), or maybe 15 with a normal feat if you're a variant human, but this feat instead boosted that to an insane 22 average.
This doesn't even include Extra Attacks, opportunity attacks, unarmed strikes (hello monk), things like haste, etc. I'm not even sure if Blobby's recommended 1d4 would be balanced, but 1d8 surely isn't.