Yep. But reductive doesn't necessarily mean bad. A gastrique is reductive too, and quite tasty when properly applied
Oh, that's a good one, but I think you know where the potential for fallacy lies in a reductive argument.
Let us take... Cosmos, the old series starring the brilliant Carl Sagan - arguably the most intelligent TV mini-series ever. Premise? "Geeky man explains the universe to the masses." Several shows before and since have tried that, and weren't worth the effort. Unless you realize exactly who that man is, and what production values are going to back that show, and how good the scripts will be, it sounds like a dumb idea, sure to flop.
You can put a spin on anything, but that doesn't prove all premises are dumb, simply that it's not hard to make something sound dumb if you try. Conversely, marketing agencies are often able to make the most vapid works of fiction sound as if they were based on deep and intriguing premises. This does not, however, support an assertion that all premises are inherently deep and intriguing.
Indeed, that leads us to a far better indicator of a dumb premise: listening to someone who has no interest in demeaning the work attempt to explain its premise.
Johnny Carson used to have a yearly bit on the Tonight Show, and likely Leno does too, where he would read TV Guide's fall schedule. The premises of shows were written in an objective voice, but some clearly sounded dumber than the rest. "An ex-cop back from the dead solves crimes with the aid of his indestructible talking car" is one that will always stay with me, because I'd never heard of Knight Rider before then. Sounded so goofy I could've sworn it was a comedy.
But I can certainly describe Cosmos and many other shows in an objective, netural without them sounding dumb. When I heard the premise for Breaking Bad, for instance, it sounded like a clever idea to me. OTOH, shows like Knight Rider or Once Upon a Time actually need some spin to sound less than rididculous.