The false drama with the tombstone is very heavy handed; they've sorta blown an awesome villain by dragging him out at every turn and making him seem far less menacing and otherworldly than he did when cloaked in mystery; they've stretched about ten episodes' worth of flashback over the entire season; the fight choreography has taken a nosedive (and on that note, Oliver now routinely gets severely challenged by the kinds of foes he once mowed through and there is very little of the titular arrowing nowadays); and the CW romance crap is far worse than ever. I've come to dread scenes with what was once my favorite character (Felicity).
On the flipside, Laurel, Detective Lance, and Diggle are all killing it this season, and the crossover episodes with Constantine and Flash/Legends were pretty great. Aside from that, I'm definitely looking forward to the show less and less with each passing week (and that surprised me after the season got off to such a strong start!).
Sorry for any weird errors or lack of detail--typing on a phone sucks :-)