Lots of problems here. Length is a biggie because it immediately effects some of the most important foundations of the swing, namely the setup. I have a friend that plays with me and he uses his grandfather's old set. His grandfather was a tall guy, and so is my friend but his posture sucks. Why? Because his clubs are so short he has to lean over a ton to get set to the ball. The result? He has a hard time making a decent shoulder turn.
If you can't get set over the ball properly, I don't know anyone can make a decent swing without making a ton of compensations. Also, with the launch monitor and other fitting equipment we know more about the swing than ever before. I just want to feel comfortable and balanced over the ball. In my opinion, a logical first step in order to achieve that is to have the proper length shafts that are good for you, and not what some company madates as 'standard.'