This show had some good stuff, mainly in the opener and the finale. But "inconsistent" is definitely the word to describe it. It was like RTD and McTighe didn't actually talk to each other when writing it. Stuff would be introduced then dropped the next episode (or in the same episode.) There was one scene where Salt briefly turned male then turned back again. Obviously I knw that some amphibians can change their sex (I've seen Jurassic Park!) but what was the point of it happening when it's never mentioned again? I thought maybe her and Barclay would have talked about it later during their romantic scenes in episode 4 - enterining a new relationship with someone who can change gender could certainly lead to interesting discussions - but there was nothing. And the whole thing where Homo Aqua dumped all the waste back on Earth at the end of episode 2? That SURELY would have killed thousands of people (or more!) if it was happening in every city on Earth. But it just happens then isn't mentioned again at all. We see a memorail to the people who died in the terrorist attack but nothing for the many more people who would have been squashed by anchors.
I'm not sure what the show wants us to come away thinking of Homo Aqua? At first it seems like they want mankind to change their ways and stop polluting the water and contributing to global warming, so that's good! Their methods might be harsh, but they their goal is positive. But then it turns out they're actually melting the ice caps themselves to flood the Earth and drown us all? So, umm, maybe it was kind of justified to kill them first? Salt says something to Barclay about how she didn't know that part of the plan ("tides within tides") implying that there's some shadowy conspiracy going on with the fish people too, but we never actually get any scenes of fish people interacting with each other without humans around, or any real looks at their fishy society.
But the worst part of the show was the political stuff, becaue it was impossible not to compare it to Children of Earth and this was very very very inferior. Remember how great Peter Capaldi was there and compare that to all the dull characters we got here instead.
Jemma Redgrave did do some good acting but yeah I can't see how Kate stays on as head of UNIT now. Gugu Mbatha-Raw impressed me the most and her scenes facing off with Barclay were the best part of the show. Russell Tovey had good moments with her but would sometimes fall back into doing his comedy "who, me!?" type face.
So yeah it wasn't that good, really!
Even though I think I liked it a little better than you I can't fault most of those comments.
Was it originally planned as a longer story I wonder but they only got funds for 5 episodes so had to strip it down? That happens all the time, I mean it's happened to RTD before (It's a Sin was originally supposed to be 8 episodes but they were only able to do 5).
I think you're right, a story like this needed more sight of the Aquakind side of the fence. If the antagonists had been Russians you'd have had lots of shadowy meetings, Salt clearly being kept out of the loop etc.
In Children of Earth it didn't matter about any alien machinations. We were never supposed to remotely empathise with them. They wanted to use our kids as narcotics. They were the bad guys, no ifs, no buts, we were never supposed to see their point of view.
With the Aquakind it was different, we were supposed to understand them, possibly even root for them (to a degree) but we saw so little of them, we barely even got to see their city before Leo from Silent Witness blew it up.
And yeah what was the point of Salt turning male? I mean there's an interesting throughline there about gender fluidity that I'd have expected Russell to run with but he just forgets about it almost immediately.
The idea of an ancient species that were here first and now want to reclaim the Earth is interesting.
The idea of an everyman hero who's the wrong man and the wrong time but becomes the right man at the right time is interesting.
Two people from opposing factions who fall in love is interesting (and as a story long redates Romeo and Juliet)
Government conspiracies are interesting.
It's just here at times that all these things became a trifle dull.
BUT It wasn't awful by any stretch of the imagination. Compare this to a complete disaster like the MCU's Secret Invasion.
Redgrave and Mbatha-Raw were both excellent. I'm not so sure about Tovey. I like him as an actor (he was fantastic in American Horror Story: NYC) but I think he did overplay the goofy everyman here, whilst also somehow playing the buff romantic lead and it never quite felt real.