The Chronicles of Amber has long ranked as one of my favorite series ever, and I've been waiting for 25 years for someone to make it into a movie or TV series. It looks like it's finally happening, and I'm very excited to see how it turns out.
That being said, three things are going to make or break this series. (Can you tell I've thought a bit about this?) The first, obviously, is the casting. Nobody in Amber is a one-dimensional caricature, not even the so-called "villains" of the series. Everyone has their own motives, but everyone is ultimately working for what they consider to be the good of their home, and that has to be made clear, or else the tension of the story is going to fail.
The second is the pacing: do they try to tell the whole Corwin cycle in one or two seasons? (Each of the 5 books is only about 200 pages, so that's eminently doable.) If so, then what happens if the show is successful and continues? Will they go to the fan-despised Merlin Cycle? The Betancourt Oberon prequels? Or will they branch out into new stories? On the flip side, what happens if they try to slow it down too much, but the show fails to meet expectations? Will they leave the story unfinished? Or will they go into JMS-Turbo-plot-mode, cramming 2 seasons of story into 2/3 of a season of episodes?
The third will be the special effects of Shadow-shifting and (especially) Hellriding. The first has to be subtle yet noticeable, the second spectacular without being cheesily over the top. It's going to be a delicate balance, and I'm looking forward to seeing who they bring on board to helm it and how they manage it.
(h/t the person who shared it privately)