Well, from my point of view, the problem with Java Web development frameworks is that there are too many. Each one has its strengths and weaknesses, like anything else. I'm excluding those that are proprietary and you have to pay to use them. Really, why would people pay for such kind of thing?

Focusing on what is open source, you just need to see those supported by Apache: http://projects.apache.org/indexes/category.html#web-framework

Then you can see a list of Java web development frameworks (result of a Google search): http://java-source.net/open-source/web-frameworks

There's are so many and the community does not focus on building a complete Java Web Development Framework. The one I like more is Play! Framework because it's a complete stack of java technologies that really help the development of web apps and it borrows many concepts from Ruby on Rails, which it's my favorite.

I don't know every Java web development framework, of course, and each must have their strengths and serve different purposes, but my feeling is that if there were only a few, then the community will focuses on improving those and we'll end with a truly good framework.