I completely agree that the books would require at least 6 episodes each. If GoT can do 1 book/season, then DA could do 3/per.
As for the actors… DA is fiction and we know it. There is a hotness limit, but that’s reality. Look at the average hotness on the CW — if casting specifically looks for really hot actors, they can find them.
Of course we’re not going to all agree on whether or not they made the right choices, but if Interview with a Vampire can cast Tom Cruise and get away with it, I’m sure DA can do a LOT better.