I've read the books up until Cibola Burn, so my impression comes from comparing my experience watching the story to reading it as told in print.

Season 3 was incredibly rushed through and little of any character's motivations or thought are clarified as they still make more or less the same decisions. Two noteworthy characters (Pa, Bull) combined into one character (Drummer) whose actress only does one vocal and facial expression, which I happen to mirror every time she gets air time.

Show Ashford, an arguably much more sensible and intelligent man than Book Ashford, is unreasonably suddenly deemed necessary to reflect Book Ashford without any clear change in motivation.

So many things are done weirdly on the show that didn't need be done. Those are a few examples off the top of my head. What do you think?