George Lucas is a capable technical director (maybe even a good one, maybe even a great one), but a poor acting director, and a poor writer of dialogue.
Lucas would have been better served to stay the visionary and power behind the scenes and hire more capable people to write and direct the actors in his movies. Kinda like his role in the Indiana Jones movies. No one would accuse the Indiana Jones movies of having the plot holes, stiff acting, and questionable decision-making that the prequels were fraught with. Why not do the same with Star Wars? Recognize what you are good at, and what are your weaknesses, and deal with it.