oh, "that" kind of difficulties...
i can tell, as i worked with most of the existing templates systems possible... phpBB, IPB, Postnuke, etc... and see, i'm a vBulletin developper now..

i hate complicated things.
the system parse the content of your templates, so if you write a condition wrong, it will tell you... etc
and the template editor is very efficient... CSS driver is well built too...