I've always believed that Carr can be good in a system that simplifies reads and scheme people open instead of having him throw people open with anticipation (throwing to spots). I said that Josh McDaniels caught a lot of flack for his play calling but when you understand the "complexity" of that offense, it makes sense why Carr struggled.
Every receiver on these routes is considered "live" and it is up to the QB to determine where he is going with the ball by reading the defense pre-snap and then throwing to the open receiver. If I'm not mistaken, I don't think this offense has your standard "progression" and more see and react. I'm not going to say that a QB can't still run this type of offense at it's core but with the lack of actual development, you won't see too many running this style offense correctly.
I think Carr does better when things are simplified and "structured" and it looks like what Kubiak put together is PERFECT and I'm loving what we are doing. Plus, the return of Kamara.....