I appreciate your comment.
Regarding concepts, Click has only two main concepts, Page and Control (or component) and in 2.3.0 the Behavior concept was added. So I don't think Click has many new concepts to learn but if you are after a stateful, 100% Swing type web framework then I don't think Click is what you are after.
I've started my Java career as a Swing dev and generally don't agree that Swing/desktop is easier or superior to web development. These days I'm doing mostly maintenance and I think traditional statelss web apps are easier to scale and maintain because of the underlying restrcitions imposed by the stateless HTTP protocol. Of course those restrictions carry through to how complex a GUI one can build. Certain problems require desktop type GUI's and in those situations a stateful web framework such as Wicket, Tapestry, JSF or a RIA such as GWT, ZK or Vaadin is a better fit than stateless ones.
All that said, if you are happy with your current set of frameworks, don't change a thing. Frameworks don't mean much in the greater schema of a large project, a hppy developer does ;-)