I like the direction of POI. There are tons of "case of the week" procedurals out there, but there's not much like what POI is now. The original premise (super agent gets numbers for a target which may be victim or perpetrator) was fine but nothing amazing. The serial elements really made the show, and I'm glad that they've given focus to that. For those that prefer the CotW stuff, it's still around. Fusco just handled a number in the most recent episode!
Arrow and the Flash are good. They're both based on DC comics properties. I've been told by a big DC comics fan that the shows do a poor job of sticking to the source material, but that doesn't bother me since I'm not a big comics guy (although I enjoy all the recent film and TV adaptations). Moreover, I know that comics have retcons and multiple universes and all that, so it's not a big deal that there are changes for the TV version.
There's a pretty big change in the recent Flash episode though.
Barry's new love interest is Linda Park. From what I can tell, Linda Park was actually the wife of the Flash in the comics... except not Barry. Rather, she was the wife of the third flash, Wally West. Barry Allen (the second Flash) was his mentor, and Barry was married to Iris West, who is Wally's aunt. So the family tree is super twisted in the TV version now.
On the plus side, not keeping with comics continuity means that we can't be sure certain things will or won't happen just because they did or did not in the comics.
As for Gotham, I'm still not sold on it. I think it's OK, but it's not as fun or exciting as Arrow or Flash. I do still wonder if they're supposed to be in the same universe though, since they are both DC properties.
I also want to give a shout out to The 100, another show on the CW (like Arrow and Flash). It started out a bit rocky, but I also quite like the direction it's taken. More dystopian drama, hoorah!