Well first off. Netflix is TINY when compared to Amazon. Their Development team is like...8 people? Maybe 10? As a writer, that is fucking AWESOME. That makes me want to come SPRINTING to them if I have any idea.
Amazon on the other hand is more like the traditional studio model. You have so many hoops and assistants and VP's to jump through and every single one of those people want some kind of say. So knowing that right off the bat helps because you know people will want to try for Netflix first (actually HBO first but that is a totally different animal).
When a script is in development with Netflix, they are fairly hands off. They will take lots of notes and remind you of shit, but they give a ton of freedom. Amazon...not so much. It isn't so bad as "Script By Committee", but it gets close.
I will say this, for anyone that played Witcher 3, they will probably have some gripes with the show. It is going to be based more on the books and less on the games.