Your take is very interesting because both went from $30m to $300m movie productions. Having total freedom versus execs breathing on your neck is a gamechanger. Whether it's about costs, cast, logistics, it's a whole new world out there.
I think Nolan was overwhelmed with The Black Knight Rises and Villeneuve did it with BR 2049. In both cases there's just so much at stake: directing the sequel of The Dark Knight, doing a Blade Runner movie in 2017, there was so much stuff that could go wrong and it kinda did. I'm not gonna give both of them a pass,
it's not always the greedy-out-of-touch-development producers' fault, but at some point being a director is just about doing whatever you can so your work is going through. Not all of them can afford being the Kingdom Of Heaven's Ridley Scott and release a "fuck the producers, here's my vision" version.
No doubt, and sometimes things can be right on the page and just don't come together on the screen. We take for granted how complicated movies are to make, and how many things have to come together *just* right to make something great. It's definitely art, with all of the pitfalls and great heights afforded to those endeavors.
The business side of movies interferes with the art of cinema but that's not always a bad thing; the creative conflicts that occur while making movies sometimes generate better results, and some of the best movies have been the most conflict ridden, hardest to make projects. Lucas himself showed that with the OT, the limits of tech and the multiple voices involved led to some of the greatest movies, whereas when he had full top-to-bottom control (and surrounded by yes men) in the PT, the results were not nearly as all-time great.
As to Nolan vs Villeneuve in those particular projects, I don't think Nolan was overwhelmed (although if there is background I am unaware of, please post it here, I would love to read it); many trilogies just run out of steam in the third movies, as creatives get tired of doing the same thing and the drive to be different/better/bigger pushes many movies outside of the creatives or their audiences' comfort zone; either they lean back too far into the familiar or stray too far from the mark (or, as I said earlier, things just don't come together). In the DKR's case, its trying to do too much. Way too much, as I thought the DK also had the same fault and was 15-20 minutes too long. DKR is where it reaches critical mass and becomes obvious for everyone else, though.
For DV, he had a nearly impossible task of making a sequel to legendary, iconic movie with one of cinema's all time debates [full disclosure: Deckard human vs. replicant is one of the first thing I posted about when the Internet made the jump from Usenet to forums]. I just disagree with so many of his narrative choices, as I find myself doing more and more as his career progresses. There are also some weird editing choices in the movie that drive me crazy. I don't think its a bad/poorly made movie by any stretch, just not one I like.
