They are very likely going to drag the books out as long as they can manage. I would suspect the whole first season to only focus on what happens on Trantor (The Psychohistorians part of the first book), hence the bleak feeling. Hope isn't there yet.
As for my "not futuristic enough" comment, the "future" of the books is basically 1950s America with scifi technology bolted on. They still use paper newspapers. They still use metallic currency (even though they barely have metal). They smoke cigars (which might come from Vega, but are really just cigars). They use nuclear fission to power everything. Men wear suits, women wear dresses. One guy takes a shower with water in his spaceship. Another guy has a calculator (like, a basic scientific calculator) on his hip and challenges another guy to do math in his head. The people are "amazed" by 3-dimensional images appearing from nowhere in a theatre (HOW IS IT POSSIBLE!?). Every dude has a secretary who doesn't get to speak.
It *isn't* the future in any real meaningful setting sense. They've got gadgets and gizmos and the mega-cities, but it's transparently the postwar US. Asimov barely bothers to hide it because his purpose in those books is not (and never was) to imagine the future. His purpose in those books is to show American postwar optimism, capitalism, and democracy as the positive, inevitable destiny of history. The USA is the Foundation, the crumbling Galactic Empire is postwar Europe, and all the barbarous kingdoms are all the third world nations the USA has to come in and teach about democracy and advanced technology.
Retelling that story as written is not only unspeakably tone-deaf to the current state of the world, but also extremely dated and essentially irrelevant. So, yeah, AppleTV will probably change it somehow, hopefully for the better.