Castle S8, this got long
I will say this for season 8: Hayley (Toks Olagundoye) and Vikram (Sunkrish Bala) were good additions to the cast, and Alexis coming into her own as a PI was a smart move by the writers. It's too bad that Martha was largely written out of the eighth season and Gates was written out completely, but what can you do? Only so much screen time to go around.
The bad: The running metaplot in this season seems artificial. Beckett put away Sen. Bracken, the man who had her mother killed, in 6x22 "Veritas", so "actually Bracken had a partner and now that partner is going after everyone Beckett ever knew" feels like an ass-pull. Worse, Beckett uses this as an excuse to pull away from Castle and take a "time out" from their marriage because Bracken's partner inexplicably just knows when someone knows about an investigation into them, so Beckett can't risk Castle finding out.
I do not buy a magical omniscient threat in what to date has been a fairly grounded procedural, "Castle" writers.
So we get eight or nine episodes (looking back, I can't actually remember when they get back together) where Beckett and Castle are separated, and Castle pulls increasingly-absurd hijinks to get Beckett back because she didn't tell him why she left. They only get back together after Castle tells her point-blank "this was a really fucking stupid decision you made". And even after they get back together, they have to pretend they're still separated because, again, magical omniscient threat.
I can almost forgive all that. Once you get into a metaplot in a show like this, it's really hard to get out of the habit of having one, even after you've wrapped the original metaplot up.
But the finale.
Beckett and Vikram have spent the whole season going "hey we have a lead on LokSat" (that's the code name of the magical omniscient threat) "-- oh, no we don't". So in the finale they finally actually get a solid lead, only it turns out it's a setup, and Beckett and Castle barely escape thanks to the intervention of ... a guy we met twice, eight episodes ago. And this guy turns out to be LokSat.
Throughout the show, the writers have been pretty good about following many of the traditional rules of writing a mystery, and one of the rules they follow most consistently is that you have to introduce the real culprit early in the story. It's got to be someone they've already talked to and dismissed. Having LokSat be Mason, the guy Castle met twice eight episodes ago in a completely unrelated context, breaks that rule. It makes the reveal unsatisfying. If Mason - who presented himself as another PI - had been helping Castle throughout the season, it would have been a different story.
Which is why LokSat should have been Vikram. He was implicated at the very start, but convinced Beckett he was innocent. He's been helpful throughout the season, but every time he tries to get a lead on LokSat, it mysteriously fails. Having him be the culprit, using Beckett to ferret out weak links in his organization until she'd exhausted her usefulness and it was time to kill her - that would have made a much more compelling story.
And then the final fight - Castle and the cops are trapped in a room with LokSat's agents firing at them, Castle escapes through a back wall and catches up with LokSat and Beckett in the basement just as LokSat's about to kill Beckett, and he distracts LokSat long enough for Beckett to wrestle LokSat's gun away and then knock him out with a single punch. There's no extended, pitched battle (that's happening upstairs with the cops and the agents), just "hi!" punch and it's over.
(And the cops survive because... as we hear later on the news, more cops show up out of nowhere and surround the agents. It's out of nowhere because it was established earlier that the building is a dead zone for cell phones, walkie-talkies, etc., so nobody could have called for help.)
And then the writers get one last twist in; Castle and Beckett get home, a LokSat crony they thought was dead shows up and shoots Castle, Beckett shoots the crony but gets shot herself, and they lie together on the floor, holding hands, and bleeding out...
and then SEVEN YEARS LATER, the caption says, as Castle and Beckett play with their three young kids.
What a goddamn mess. The show deserved better.
Castle S8, this got long
@noelle unfortunately, the behind the scenes drama ruined any chance of better happening - specifically the apparently inability for Nathan and Stana to be in the same room for more than thirty seconds at a time... which seems to have primarily been his fault; he seems to have decided that he was the star, and was pretty much on the point of forcing Stana out altogether (s9 was contracted, she was not) when someone saw sense and cancelled the thing completely - hence the two minute babies-ever-after at the end, rather than an unresolved cliffhanger
Castle S8, this got long
@thamesynne Yeah, I remember that feud and those rumors, but I'm not sure it played out quite that way; Katic had also demanded a substantial pay increase for S9 which the studio was unwilling to subsidize, and Fillion at least seems to have no lasting hard feelings toward her. I don't think there's any doubt that they don't like each other, but from his more recent comments I don't think he tried to torpedo her career. But yeah, I get why they filmed the babies-ever-after, I just thought on hearing "they filmed two different endings" that that's what the writer actually meant and not "my ending is pastede on yey".
Just Ellie (and perhaps some of her toys).