In enterprise Java there are quite a bit of tools/frameworks designed to do this. While I don't particularly like the one they use at my company (bloated quirky IBM code-gen tool), it makes me see the merits of this approach (everything is basically a single page app & sections of the page are only replaced as necessary -- it is a Portal solution). Between that & seeing the JSF/PrimeFaces components my friend is always messing around with, I see the breakdown as 2 camps really -- People who like to write js vs. people who don't...

For the people who do, pushing data & logic into the client is fun, working with js, working on the actual "single-page app" & updating logic/css/html simultaneously.

For people who are more into static typing / web back-end, & don't particularly like the process of writing js, there is a nice movement toward dynamic pages where the updates are concocted through data-binding & behind-the-scenes ajax (generated by the component libs...). For a lot of enterprise Java devs, the dream of having an ultimate single source of domain logic in the Java layer somewhere lends itself well to this solution. You code typical OO paradigm and just try to integrate those models naturally into the front-end binding.