This is similar to what I often feel, that I have nothing to say. It gets in the way of finishing things. In a way it helps me to know that my insecurity is shared by someone with your obvious ability.

Another LJ friend of mine who has a couple novels getting published now says the solution is just to keep writing anyway. If it feels lacklustre, just keep working. You can revise it later, but it's better to put something down than let the writing muscle get soft. This is the discipline I'm struggling with now.