I agree and disagree with your statements. The reason I say this is I have seen people shoot very well with draw lengths that are too short for them. If they are too long then they normally have troubles shooting accurately.
I think if you are shooting a draw length that is wrong, you can learn to shoot it with a ton of practice. You will have to work at it a lot.
Now, if you take a person and get them setup with a correct draw length, reasonable accuracy will come much quicker and will will seem easier to the shooter. Little form flaws will not have a huge impact on the accuracy.
Another reason I say people can shoot the wrong draw accurately is we got beat badly by a team at an indoor 3D this weekend. The one guys bow arm elbow was bent quite a bit but he shot extremely well. How well, how about consistantly drilling 12's and 14's at 37yard jake turkeys.