Since we're discussing DC Shows... even though a dedicated thread for that as well...
In alphabetical order
Arrow - I'm still a fan. I guess I like the characters and the world enough. I do think they need to kill off some of the main cast and get some new blood in there. Not because I dislike many of them, but because I think it was a problem to make them all involved in the heroics of the show.
It nerfs Oliver's fighting, and then it really drops a lot of the personal turmoil. I know folks don't like the drama, but it's nice for the characters to have something else to do aside from the case of the week business. And when they are ALL in the know, the show tends to focus on that.
And yeah the flashbacks which were good in season 1/2 have become more and more of a pace killer because they hardly relate to the current day events so just feel jarring.
Gotham - You either get or don't get Gotham. I mean there's hardly any middle ground. And I don't mean it's a show you give time to get better (though season 2 is so much better), but it's a show with a tone so unique to it that people sometimes have trouble reconciling that with their expectations. It's not super dark and gritty, but it is... it isn't super campy, but it is. I think people were thrown by that and it has been hard for folks to overcome that. But I love the show for it. It's really unlike anything else on television in its sensibility.
iZombie - A show I dig, but also find it can be tiresome since the whole joke with different personalities can be trite depending on the week. And it always seems to create drama for her relationships at the right time. That said the cast and writing tends to be on point!
Legends of Tomorrow -Now this is a show conflicted on. Love it. It has exceeded my expectations. But even 4 episodes in, it's starting to feel like the show lacks forward momentum at time. Like it feels a lot more procedural than its counterparts. With the chase for Vandal and having to split up the team and the in-fighting. But like said only 4 episodes. Could really start mixing it up soon.
Lucifer - It's a police procedural with a charming lead. Not my cup of tea, but works for some
The Flash - I don't think anything else can really compare with this show since it gets to play on the insane portion of comic books like nothing else on TV (or heck even in movies) It has the most jaw-dropping moments of any of the other shows. The cast is great. The heart is there. The drama never lasts long enough to wear out its welcome. Unlike Arrow where everyone is involved in the heroics, only The Flash is really involved in the combat aspect of it. Great time for the most part. Though really need to work on the Barry/Iris stuff.
Supergirl - Had a rough start, but since finding its groove has really found its groove. The supporting cast are the stars with Cat and Hank being the best two characters, but the team all gels well. One big mark against it is the weird love triangle/square or whatever. It isn't needed and really drags down some interactions.