Oh, from a storytelling standpoint in absolutely has to be the next part. Otherwise you've got an Embrace the Darkness lull. However, we've never had the Doctor, C'rizz and Charley just having adventures in the TARDIS. Everything has been travelling along the Interzone. It'd be nice to see that. Hopefully with Dark Eyes coming to an end Big Finish can maybe journey back to this time for a couple of light hearted adventures that explore the difference in this other universe. Then again, there's another eight episodes of this trio in the TARDIS still to go, so maybe that scratches this itch.
Anyway, the end of the Divergent Universe. It should come as no surprise that I'm not sorry to see it go. Thankfully The Next Life doesn't go down the same hole that Zagreus disappeared down. It does take a lot of cues from that fan-wank though. It's an especially long serial for the Eighth Doctor, but only just so. And it features the return of Rassilon, and more importantly Zagreus itself.
The original premise of the Doctor coming here was the he was infected with the Zagreus energy and the Divergent Universe was the only place it wouldn't run riot and start messing with time again. Turns out that just a few moments in this new place meant it could be free of the Doctor and now has the handy ability to inhabit dead people. This being the Divergent Universe they're not undead, just with a different personality in the driving seat. So it habits the most perfect woman ever, unsubtly called Perfection, and proceeds to manipulate things to try and get back to the normal universe where its powers would be back at full.
We also get some serious time with C'rizz, as we meet his father and get a look into what his duties were as a monk of the Church of the Foundation, and they weren't very nice. Not much more is done with this, except for getting C'rizz to switch sides for a bit as he's manipulated by his father. I hope this gets addressed now we're back in the proper universe.
Then there's Rassilon, who's apparently been puppet mastering this whole arc from day one. Turns out he's the Kro'ka's master after all, not the Divergents. His manipulation of Charley is great, and while it doesn't work with C'rizz, something else does. Basically The Next Life becomes a ton of puppet masters with all their plans coming to a conclusion at once. Which is to be expected when the end of the universe looms. However, they all come out of nowhere, and there's just too many threads for any to have a decent impact. This kind of story needs proper set up. At the very least more of C'rizz's religion should have been explored first, and the hints about his father and the fate of his family given more time. Instead it ends up a mess because everything kicks off at once.
Apparently the decision to end the Divergent Universe here was made by Big Finish on short notice. The original plan was to have another one or two seasons here, but with the BBC commissioning the Russell T. Davies helmed new show, they changed their minds in order to make their audios more new-listener friendly. That's really obvious here as they try and do far too much in order to end the saga.
On a smaller, TARDIS centric, side, on top of what we see with C'rizz, I love the shift in the relationship between the Doctor and Charley too. While the last season ended with them admitting their feelings in the face of death, their continued existence has proven that it couldn't go anywhere, and their time in the alternate dimension has helped Charley realise this. Now instead of that love, Charley and C'rizz are treated like bickering children. It comes from a genuine place of the two losing their trust in the other, and had it slowly regained to now be in a position where they can be friends again, but still not entirely sure of the other. It adds a nice fun element to their conversations that has been sadly missing for the majority of their first season together.
The Next Life wasn't all that great of a season closer. Especially as the Divergents, who have been teased since Zagreus weren't even featured, having been defeated by Rassilon off screen. Another thing it has in common with Zagreus is that the preceding part of the saga, Caerdroia here and Neverland before, was so much better and answered so many more questions.