* Way too damn long. Felt like trying to game the system to gain more watch minutes. Every episode could've been trimmed down. Also at least two subplots needed to be cut. While the Hopper one got fun (in a very 80s way), I'd have kept him dead a season, streamlined his return in 5. And the Suzy subplot makes zero sense, seemed to exist mostly to show off her Goonies-inspired family, but ultimately nothing to do with the main plot or themes of the show. Purely a sidequest to give the characters something to do.
* This isn't Potter--with the exception of Max, the precious child actors have not aged into decent actors. Mike and Will are basically charisma vaccuums. Dustin's schtick was cute when he was a kid, not at all believable for a high school freshman. When they don't have other actors to carry a scene, it's ugly.