I'd classify Nashville as great. For a movie with that many characters and storylines, a really impressive amount of them resonate with me. I think there's enough good music to make up for the sub-par songs too. I love the "My Idaho Home" performance so much.
I think all of Battleship Potemkin works actually. The "Brothers?" finale is tremendous. Early 20th Century Russian propaganda films FTW. I haven't seen anything else by him, but I'll check out October.
I don't know if I'd go as far as to say "The Departed" sucks, but it's definitely lower-tier Scorsese. "The Wolf of Wall Street" sucks. Actually, it's better than "Shutter Island" too. But anyway, I think the plot idea is too good to really be turned into a bad film, but both The Departed and Infernal Affairs are lacking in certain areas. The original has those really hokey musical cues and flashbacks when someone dies, and if anything the characters in that one are underdeveloped. Like, the undercover cop's relationship with the psychiatrist in that one is really cute, but they have like two scenes together. Meanwhile, The Departed is too long and silly, features a ridiculous Jack Nicholson performance, and has two too many people getting shot in the head at the end. I want a middle-ground version that features the best elements of both.