@ajfirecracker I think you make some fair points.
I think Powder is underrated in vintage. I have run it in non-dredge decks I find it very hard to evaluate how Serum Powder affects a deck... Powder's drawbacks are very visible, but its upsides are hard to measure. I'm still unsure on the card, but I feel like most players haven't seriously considered it in any way.
I do think Dredge is uniquely qualified to ignore the downsides. Bazaar makes the card quality disparity super high, can filter away dead Powders, and Grave-Troll very quickly compensates for the CA disadvantage.
Also I don't think that it's completely incomprehensible for a card to have huge raw power but not be playable in every deck. Mishra's Workshop is a clear example.
But all that isn't to say that Serum Powder has no drawbacks. For sure it does. I'm confident it's still right in Dredge but I admit it's not a clean argument.