I'm actually pretty happy with season 5 so far. Having a metahuman(?) on the team with a mystical "holy vengeance" mindset and personality is a nice contrast to the more realistic characters. The fights and stunts are nicely done and the editing and camera work shows off more of the choreography instead of being lost in choppy editing.
People (read: Reddit) whine about how the show is going backwards with Felicity's dominance in the story and Oliver killing again, but it's not nearly as bad as the Olicity soap opera stuff. I kind of like that Oliver is being a tough bastard who kills and it goes to show that a no-kill rule is really really hard to keep. Unfortunately the only "voice of reason" character the show has is Felicity (and maybe Thea, but she's out of Team Arrow right now and Diggle is away), so Felicity has to take that role, but we get annoyed with her because of all her previous baggage. Like, if it was Diggle telling Oliver what to do, we'd be totally fine with it.