Suggestion:
make PHP to be integrate into other programs.

Jscript/VBscript of M$ has been made into a DOM object, named ScriptingHost,
programs support DOM could invoke Scripting Engine freely,
I'm excited to hear that, php can run as shell language
but why not make it easy to be integrate into other programs ?

PHP script is powerful in TEXT processing, which needed by RPG game
but PHP can't host as an RPG game (now)
two way to do it
1. just like GTK did, make extends for PHP to control DirectX/OpenGL, but PHP isn't low level language.
2. make project using, and it use PHP script to control, but recently, i havn't seen one PHPScriptingHost for Application.(maybe i lost? :P )