ui:composition with EL works for me.

Just tested the following simple test:

with a req param called page with the value /WEB-INF/layout/template.xhtml

<ui:composition  xmlns="http://www.w3.org/1999/xhtml"
      xmlns:ui="http://java.sun.com/jsf/facelets"
          xmlns:h="http://java.sun.com/jsf/html"
          xmlns:f="http://java.sun.com/jsf/core"
          xmlns:a4j="https://ajax4jsf.dev.java.net/ajax"
          xmlns:rich="http://richfaces.ajax4jsf.org/rich"
          xmlns:s="http://jboss.com/products/seam/taglib"
          template="#{param.page}">
                

        <ui:define name="body">
                #{param.page}