When I first started to work with web applications, it was just servlets and then came JSPs. At the time, I didn't like JSPs (and to this day I still don't). They seemed like a necessary evil that got the job done. The thing I found repulsive about them was the mix of server and client code together. The switching of contexts just made both look ugly and hard to maintain. But, it was easier than generating pages directly from servlets by hand. Of course, there were other solutions that I looked for, but nothing got away from the horrid markup. Then, I fell in love with Seaside which did away with markup and generated content through a custom DSL. It felt better to me and loved it until I realized that it was only for the developer, not the web page designer. It made their life harder. Now, we all know we should use minimal content and have CSS do the layout. But, in this modern world, you need folks who are experts at web page design. You can not and should not alienate them.
My feeling is that the days of template engines are over. It's a waste of time and all of them are a pain to debug. A pure Web 2.0 AJAX solution allows each to utilize their tools and do things separately. To me that is exciting and I will gladly leave ugly code behind.