Alrighty I got yet another idea for a thread and again it is kind of negative so I hope no one takes offense!
What comic creators do you feel never lived up to their potential or otherwise disappointed you in some way? I am thinking mainly of people who were really good at doing comics but for some reason left the medium. Examples would be that you were sad when Stan Lee stopped actively writing comics in the 70's or when Alex Schomburg moved over to illustrating novels instead of comic covers after the golden age.
Actually my motivation for this thread was Al Williamson. I love his work, but it pains me that he never really did a whole lot of it. He has been in the comic business for decades but has spent the majority of his time as an inker. Even if he is a great inker, and is inking very good artists, I still feel a sense of loss that he didn't produce more actual artwork for publication. Other examples I can think of would be Mark Schultz and Dave Stevens, who both slowed down their output tremendously.
So what comic creators are you sad didn't do more work (or do better work)?