1) Fight sequences remain top notch. The staircase sequence at the tail end of episode 3 should rival anything ever done to this point. It doesn't have the same resonance for me as the fight at the end of episode 2 in season 1 (the hallway fight). But it's still ridiculous. Fights with Punisher, fights alongside Elektra, fights by Punisher/Elektra, all pretty good. Several fights with the Hand are interesting/impressive.
2) Murdock as a character isn't well constructed this season. They make a very small reference to him being okay with people being killed. But unlike season 1 where there is a long-drawn out conflict over murder/vigilantism internal to being/becoming Daredevil, there's kind of a short couple of conversations where he goes from nearly getting Elektra killed in order to avoid killing to now letting Stick/Frank/Elektra kill people alongside him and him essentially trying to kill Nobu. Because he has to? Because they're all trying to kill him and there's no legal system to deal with the Hand? Because he's suddenly fighting a war against legions of katana wielding ninjas? It isn't made clear what flipped this switch other than that he now has flipped it.
He has some really vague and poorly written sequences intersecting with his legal career. The DA putting the firm on the shit list doesn't really seem like it would have any real impact. They have really weird clients anyway and Elektra gives them a cash infusion. I don't understand how they would notice a drop-off in work or a major change in the bills. The Punisher case is handled strangely throughout, clumsily used as a plot device to give Foggy something to do to distinguish himself from Matt, and eventually leave to do more important things in future seasons/other Defenders series (one could see him popping up in Luke Cage/Jessica Jones pretty easily as another crossover character like Claire). Foggy is thereby well written therein (both in the trial and in the earlier sequence with Claire at the hospital), but Matt's "questioning" of Frank is lame, the overall handling of the case makes little sense (they basically repeatedly ignore that their client won't play ball with the defenses they have planned, and then put him on the stand?), and the entire plot line involving the DA doesn't really fly either as it feels like an extremely ham-fisted attempt to cover up something throughout.
3) Karen is also written very strangely. I did not mind her poking around in the Punisher case and developing a rapport with him. I did mind the "article" she writes at the end, which wasn't a news article. It felt more like a high school speech. I did mind that they kept using her as a plot device to place someone in danger for Daredevil or Punisher to come rescue (lazy). She nearly freaked out in the first season after someone tries to frame her, and then kill her, a fairly ordinary response to danger. So how's she going to handle nearly being killed 4-5 times in a couple of days? This was setup by basically making her kind of shrug the first time it happens (after Frank nearly kills her), but it isn't much of a changeover (much like Murdock's change on killing). I do think they've set up a Born Again plot with Fisk and her past and her knowledge of who Daredevil is. But while she has good investigative instincts, she's not a reporter. That whole plot line made no sense as a result.
Claire's departure from the hospital also is handled strangely. There's clearly some kind of setup to indicate that the Hand bought off the hospital administrators to hush things up, but we don't really explore that (nobody thinks to mention this to Murdock or Elektra?). She remains one of the better characters in the show when they use her, but her reaction to setting up a special wing to care for some curious patients on DD's behalf doesn't really make much sense. Note: I would expect her to show up in Luke Cage later in the year. Even though he doesn't need much medical care/help and he seems the most balanced ethically of the four-five major characters that have been introduced (DD, Elektra, Frank, JJ), he will be around people who will/might.
4) Frank/Punisher is by contrast pretty well constructed. He has a straightforward setup as a character. And he more or less owns most of the sequences he is in, basically the first four episodes, plus two more. They left enough unanswered about the character that it will probably be a spin-off series of its own soon enough. They gave him a pretty weak send-off in the finale, as he shows up to snipe a couple of ninjas and show off his trademark armor and then go off to do other Punisher things.
5) Elektra is often not given much to work with as far as the writing/setups for her character. I wouldn't blame the actress so much as the material being sort of meh. I think Jennifer Garner did about as well with far worse material in the previous incarnation of the character, but there's going to be more time to get this right and let her flex a little more. She doesn't really have a chemistry with DD other than that she is a catalyst for everything else (she is literally a plot device a couple of times, much like Karen is). I suspect part of the problem is simply the awkward way DD and her interact at times and her sometimes playing a (weakened) love interest and then sometimes playing an aggressive and dynamic female character. The change of paces that involves don't usually make sense and often slow down too much from fight sequences or some other dramatic event (when she kills the ninja in Murdock's apartment for instance).
She's supposed to be a super-bad-ass fighting machine, then Nobu and a few ninjas nearly take her out a couple of times so she comes off almost like a damsel in distress half the time instead of being pretty resourceful and crafty as she comes off the rest of the time. She's given a sort of wild child edge most of the time which it starts out more interesting and then goes off into "ah ha, plot mcguffin territory!" instead of that being a balanced and well-defined character trait. Contrast this with the way Catwoman may be the only character in DKR that works, in large part because there's a clearer arc for how she interacts with the city/villains/heroes despite being an anti-hero of sorts throughout in her actions (there's a similar parallel to her being fine killing/using guns and Batman finally overlooking this).
As an added bonus though Elektra looks a lot cooler most of the time. DD's suit still needs some work here and there (the look in black for most of season 1 still destroys his armored costume most of the time for looking awesome. Though getting the billy club was a nice touch).
I did like the Hand fights where they figured out DD's weaknesses and exploited them, and that he learned how to compensate, but Nobu was "generic comic book villain in charge of a shadowy organisation" for most of the series once he shows up. Several of their activities weren't really well explained. What's that giant hole doing? What were those infected kids doing other than looking like a bad Halloween movie? What are they doing with the hospital? Why are their warriors previously dead guys? Why doesn't DD buy into the mystical bullshit? (he's religious, so he already buys some mystical bullshit, and he's up against some really freaky opponents who can mask their movements, heartbeats, etc). Few of these are well examined. One imagines because of how the season ended, some of these questions will be answered and examined later. But so far they're very unsatisfying.
6) Fisk's two episode cameo was very unexpected and very good. I approve. Though it also gives some suggestion of how weakly the Nobu/Hand villain plot line was handled. And the Blacksmith arc for Punisher.
Overall I'd say something like a 6 or 7/10 for this season, and maybe 8.5/10 for the first. The finale last year maybe lowers it to 8/10, but it's much more tightly constructed as a season of events where this sprawls and doesn't do quite enough running to cover all the ground while also expending a lot of time dropping leftovers for the next series/seasons. There's a couple of very good episodes (early on there are two in particular, and one of the later episodes involves some nice touches on the morality of what's going on). But they're all good largely because they're practically Punisher episodes (or involved Fisk). Which almost certainly bodes well for creating a spin-off series, but doesn't bode well for working with the DD characters/arc.