Foundation is a series of short stories taking place over millenia, mostly people in a room talking about things that happened elsewhere, long ago, or talking about things that will happen in the future - none of which happen "on stage."
Asimov - and I love Asimov and have a shelf full of volumes - was, in his sci-fi, a writer of ideas, but not a writer of action or character.
Which means anyone adapting Foundation is going to have to cut away to battles and events and add in a bunch of character nonsense that had nothing to do with anything Asimov wrote. This also includes women and not-white people (I can think of exactly one prominent female Asimov character - Susan Calvin from the Robot stories, who is specifically described as "mannish."). Asimov, btw, never dealt with sex in his tales.
One can take the basic premise of "Library of Alexandria in space," and make a good show, but it won't be Foundation.
Such has been my opinion since it was announced last year.
I don't have Apple TV so shan't be watching.
To address Red's comments:
Showrunner/lead writer is David S. Goyer. You can peruse his IMDB if you wish, but, of everything he's written I've seen, only Dark City and Batman Begins were things I've enjoyed. Seeing his name on a project pretty much tells me I won't enjoy it, because I've seen a couple dozen things he wrote I didn't enjoy. In general, he never seems to understand what made the original work when he does an adaptation, and he's done a LOT of adaptations. He sure as hell doesn't understand Batman or Superman - watch "Batman v Superman" for proof.
Don't watch "Batman v Superman." It's terrible.
Can't comment on the acting, but I am surprised. Jared Harris (Hari Seldon) was quite good in Carnival Row, Robert the Bruce, The Expanse, Sherlock Holmes: Game of Shadows, and other things I've seen him in. Lee Pace (Brother Day), did fine work in the Hobbit movies and Pushing Daisies. Terrance Mann (Brother Dusk) impressed in Sense8 and Dresden Files.
Reviews... It's interesting glancing through those. Reviewers unfamiliar with the original either love the visuals or find the story "old fashioned" (Old fashioned? No duh, it dates back to the 1940's and Lensmen is the only earlier property I can think of offhand that was really about Galactic Empire."). Reviewers familiar with the original basically bear out everything I said above - that the show has merits, but it's not Foundation. One reviewer, who saw the entire season noted that the entire ten hour season basically covers the first hundred pages or so of the first volume. 100 pages over ten hours? I shudder to think of the padding and unnecessary subplots.
Oh, right, because Foundation is historians saying "Well, that fell apart, and things are gonna get worse, so lets build a library!" followed by librarians saying, "well, everything fell apart, aren't we lucky to live in the library," and, "Oh, crap, Seldon didn't predict everything, what's THAT guy going to do," and, let's not forget the prequel novel of, "I'm working on this thing called psychohistory, but it's not done yet."