A nice piece overall.
The first problem, without a doubt, is always the script.
As long as the script is flawless first, everything else will fall into place.
I'm trying to think of an amazing script that ended up being a terrible movie, and I'm drawing a blank. Great Script -> Bad Movie ... not sure that exists.
The script, when completed, brings all the elements of acting, directing, cinematography, set design, costume design, music, editing, sound effects, together.
Visually speaking, the only anomaly to this is Public Enemies, for its digital brain-fart... but that was a completely separate issue from the script.
Script is key. Writing is key.