JSP builds an architecture on top of servlets, and because of that dictates to some extent how pages are created. Yet there are alternatives. ECS uses a drastically different approach creating a page as a set of Java objects. Turbine uses a central servlet dispatcher. Cocoon and XMLC use XML for content creation.
Different styles work better under different conditions.
JSP dictates style. Style is a dangerous thing to standardize. Programmers tend to fall into this category, as well as a significant portion of html designers. JSP syntax, as it stands now, IMHO, is a drag to learn, type, and look at. Discussions like this may help expose this as a shortcoming that could be addressed.