(sigh)...Well, that was a Chibnall series finale, wasn't it?
I'd say I was underwhelmed, but my expectations were low to begin with. As it turned out, well...that was simply DREADFUL. Utterly lacking in imagination, completely insipid, almost entirely without emotion, and thoroughly uninvolving. That was almost like watching an episode of Doctor Who written by algorithim. I kept waiting for a plot twist to hit, or an interesting concept to rear it's head. Alas, I'm still waiting.
The main problem with bringing back the Stenza is that he wasn't remotely interesting the first time around. He's a generic killer with zero character. He's not the Weeping Angels, nor he is the Silence. He isn't even the Monks. My heart sank the second he was revealed as the bad guy.
The Stenza's plan involving the five planets was exactly the same...EXACTLY THE SAME...as the one employed by the villains of the Fourth Doctor story 'The Pirate Planet'. The big difference, however, is that 'The Pirate Planet' was written by Douglas Adams, whereas 'The Battle of Racoon Coal (or whatever)' was written by Chris Chibnall.
That episode had absolutely nothing to say. Doctor Who should never, ever, be boring. To be boring is the cardinal sin of Doctor Who. Sadly, we appear to be stuck with a showrunner who can only hit 'boring' at the height of his powers.