Season 3 was horrible

Season 1: a bloodier, more cynical take on Buffy/Vampire Diaries/True Blood with momentum, intrigue - interwoven arcs, mystery, big bad, climax
Season 2: meandering, barely justifying the leads having anything to do with each other, very mediocre
Season 3: six unrelated storylines that crawl so slowly they practically stand still, extremely repetitive, no energy, idiot characters (would s1 Peter keep so much from his cousin?), replay of s2 Olivia's illness including using her daughter, nearly forgets about Spivak storyline

Usually it takes 3-4 seasons for a great show to go bad. Hemlock Grove fell down a flight of stairs in season 2 and fell off a cliff in season 3.