I get their reason for doing it...
It just seems an odd way to go. Your illusions practically EXPLODE... and somehow that causes you to gain a defensive boost.
Saywha?!
It could be argued that stunning them isn't different enough from dazing them.
What about a knockback? Or a fear?
Hell, if they wanted to keep it defense-oriented, the fourth one should apply weakness. Which would, however, call for a shorter CD.