Java/Tomcat is an unsavory prospect for many folks. The options for building the server side are numerous; Tomcat is a clunky, resource-hungry PITA that many folks, myself included, go out of their way to avoid. If the devs are Java guys then that's their business, but the choice will almost certainly decrease the user base.
Yes, this is the kind of feedback we're looking for with regard to another comment here. This is why we haven't committed to a language for the server-side reference impl yet, because we're not sure what would be useful. (Our prototype is java, fwiw.)
