You've got a bit of a moving target with a before and after comparison.
Both your instructors and your students can only get better at using a CMS.
Course design\presentation can only improve (unless inexperienced instructors teaching brand new courses are introduced).
Moodle's pedagogical underpinnings (constructivist) are considerably different, IMHO, from WebCT's.
For that matter, depending on which version of WebCT you're looking at, the difference in CMS design may be like looking at neanderthal vs. homo sapiens (I'm exaggerating a bit, but a lot has changed in a very short time).
Moodle (& Sakai, for that matter) is so vastly less clunky than WebCT 4.1 that we had a very difficult time comparing the two CMSes.