Arrow: 10 Mistakes It Must Fix In Season 5
9. Too Much Filler
23 episodes is a lot of episodes, especially for a drama. It's difficult for any show to sustain its narrative across that amount of runtime, as well as making things continuously feel fresh and exciting.
It's something Arrow has particularly struggled with over the last couple of years, with episodes that amount to little more than filler, simply biding time until they're at a point where they can raise the stakes again, or when the main villain can reemerge. Not every episode needs to have something big happen, or even impact on the overarching plot, but you can still do episodes that standalone somewhat while also developing the characters or simply being wholly enjoyable themselves. Arrow hasn't done that of late.
Ideally the show would reduce the number of episodes, to around 16 or even just to 20, but that isn't going to happen. So instead they need to work on ensuring that every episode feels important, whether that's by using more mini-arcs, creating better villains, having some serious character developments, or enough plot to last throughout 23 episodes.