JSF, GWT and various other java frameworks masked java developers from having to learn HTML/JS/CSS which is what we wanted or allowed them to do. It allowed management to resource project teams with a set of java developers for front end, back end and middle tier. In this resourcing model, one thing that it prevents is the ability for developers to get vertical and grow which creates frustration among developers. What I mean is developers don't have the time to get good, efficient or understand one slice of the stack (service, front end, middle tier, etc). In many cases when project teams are put together, the development team naturally segregates itself into front end, back end and application tiers.
As "modern web development" pushes the boundaries of development, I am sure your architects got the Gartner report by now, it is important that enterprise java development maintains flexible ways to support it. Should everything need to be a single page architecture? Should everything have the "bouncy browser effect"? Should architects have to sell the wrong things to use the right tools? What we all know is if you have been paying attention to front end development space, there has been a revolution of technologies. Various templating languages such as dustjs and mustache, front end MVC frameworks such as angularjs and backbone. These rich front ends require talent to build them and that talent, just like us java developers, want to use the right tool for the job.
It is important as huge enterprises evolve that they support this shift to retain talent and build awesome products. HTML/CSS/JS has been around and will be around for quite some time which should be driving part of your strategy. Front end development resourcing isn't a commodity, time for some change.