I wrote these thoughts yesterday before the board went to crap
The thing with Alien Covenant upon rewatching is there isn't really anything good there. Even the cinematography/designs aren't all that much more impressive than Prometheus. But that's not the heart of it, the heart of it is the theme, the philosophical underpinning. And I've seen it argued "Oh, it's about creation and the drive to create and what it means to be human" to give the movie a layer of depth because what else is there? But rewatching Alien: Covenant. It's really not about that at all. Oh they reference it. They reference it in the same way Batman v. Superman references the destruction caused by vigilantes, as a thesis statement without any follow through, but something stupid people like to pick up on to believe that they're smarter than the average audience member who saw this movie as crap without realizing latching onto the facade makes them stupider (@Jacuzzi Billy) .
However, the reason those parts (the parts about Creation) stand out is because no other part in the movie does. I was surprised by how little happened throughout the movie. Covenant only comes alive when it's Fassbender acting against Fassbender - he's the only one who brings energy and gravitas to his performance. It's kind of like Rogue One. You leave leaning positive because of the battle scene (which even I admit was well done) and you forget that 90% of it is boring inconsequential garbage.
Rewatching Covenant, I was also surprised by just how little a part and how surface the 'creation' stuff was. There's two brief segments where Walter and David jam together, but they never really delve into it in the way a better movie would/should. And even that relationship comes down to robot kung fu. But still, that's the highlight of the movie.
The rest of the movie - I don't even know what it is. It takes like 45 minutes for them to finally get to the planet, there's precious little Alien action, and the the final 20 minutes is Jason X.
I also forgot how bad the characters are - none of them stand out. In all of the other Alien movies, there's at least a couple whom have some memorable characteristics. Sometimes it's just the actor, but at least they can add legitimacy to a role that is otherwise forgettable (e.g. Theron, Elba). Covenant didn't even have that. I only remember Billy Crudup's character because of how badly they handled the faith thing and because he's Billy Crudup. Ditto Tennessee, the only character's name I remember because they repeat it every time they talk to him. He's kind of memorable because Danny McBride has a screen presence, but I felt the role was beneath him. It didn't really hit me until the alien fight on the Lego ship on the planet at the end when he's giving Generic Video Game commands to New Ripley just how amazingly well McBride can handle dialogue, particularly weird monologues - and how he was given nothing to do here. And I don't even remember the name of New Ripley. It's either Taylor, Daniels, or Wilson.
But fine Ridley. If Covenant was really David/Walter's movie. Then make it their movie and really par down the human cast and focus on the two robots more. It wouldn't have been that impossible to show the movie from Walter's point of view. But they didn't do that because either they're not smart enough to handle the creation aspect or they don't trust the audience to be smart enough to handle the creation aspect, and I don't know which is worse.
And I said this during the HitW, but I wouldn't have minded if they ripped off Alien by having the discovery of the Prometheus be a RoboCop-style fourth directive in the ship/Walter, or if David sent a virus to the ship/Walter when they played the John Denver song (a virus is as stupid an answer as anything else we were given). Not that Walter is out to sabotage them, but unlike Ash he is trying to fight his programming because he genuinely cares for them.
Also, why Country Homes? Why that song out of anything? Why that over a distress beacon? That final message she gives at the end of Prometheus, "This is Elizabeth Shaw and me and my robot pal are about to head off on some more crazy adventures to find crazy things in space like new friends in the sequels, meet new Aliens, and there'll be xenomorphs and other off brand xenomorphs and other crazy stuff in space. Maybe we'll find Predator planet. Who knows." Or if David's all about creation, why not something new and original.