This was something that I made mention of when he first signed. One of Carr's weaknesses is throwing with timing and anticipation and a part of his intermediate throw issues is due to his horrible footwork but honestly, in today's NFL, that is not limited to Carr in the least. That's why the "modern offense" requires less skill from a QB and just require them to be "accurate."
I agree with you 100% in the fact that Carr needs "static" routes and this is one of the key reasons why he struggled with Josh McDaniels. If anyone knows anything about that offense, it is E-P to the core. Each side has a route concept to beat a defense, the QB must read correctly both pre-snap and post-snap, with options and choice routes built into a lot of plays. Looking at the Vikings during Kubiak's season there, I think Carr will do good in the system but it's all about how he picks it up.