Player development - Players did not develop in many areas because everything was so basic. Imagine a college basketball team working on dribbling straight down or just playing catch vs various screens and cuts and change of directions dribbles.
The predictability was more than I have ever seen. Having various pass routes where some look the same, but are slightly different will give the receivers more space and just practicing these plays will improve the route running.
Space Management. The Rams space management on offense was so bad. It appeared that wherever the ball was, there were 18-22 players in a very tight space.
Get these 3 improvement opportunities done and nobody will recognize that this was a historically bad offensive in NFL history as it will be competent and in the middle of the pack most likely. You can't be great with average talent, but you should at least be average and in some cases, you rise to levels you didn't think possible.
This is one of the reasons I felt Martz was such a great coach. He elevated his players, by developing them and than developing the team to put players in position to make plays and using their strengths.