1) The three credited writers have little to no actual screen writing experience and it shows: incoherent plotting, poor pacing, and embarrassing dialogue.
2) The casting is terrible. Not a single actor remotely suits the character they're playing. One of many, many examples is Bill Skarsgard. He's supposed to be playing bad-boy-dangerous. He even chain smokes to prove it. Only problem is he looks like a pasty and waifish Prada model with all the menace of a girl scout. Every character is similarly miscast.
3) All the actors are terrible. They're experienced. They're not new to the whole acting thing. Yet every one of them is awkward and stilted and visibly uncomfortable. They all have that embarrassingly amateurish community theater vibe and I can't understand why. Famke Janssen's accent sounds like a Canadian Leonard Nimoy doing a Katharine Hepburn impersonation. It's just one example of the inexplicably poor choices made by every actor involved.
4) For a show about werewolves, gypsies, angels and mysterious backwoods shenanigans, there's no attempt to introduce an ounce of suspense. You know that feeling when you're watching a show and the credits role and you're giddy with excitement over how it's going to turn out and you're mashing at the keyboard to pull up the next episode? Yeah - there's none of that.
5) The whole point of Netflix producing original content is that they're not confined to the standards of TV. Nothing about this show couldn't be shown on primetime network stations: no sex, no violence, nothing that even tries to push the envelope.
6) Even at a technical level, everything seems amateurish: awkward framing of shots, shots held too long, inconsistent editing, dull and murky photography, poor music choices, generic and uninspired production design and costuming.
"Hemlock Grove" is one of those once-in-a-decade epic failures that defies all reason. I hope to God it's an aberration and not an indicator of what to expect from Netflix in the future.