I think you can work around that. For example.
Wizard/xxxxx
No Smart - Cast Infuse Vital Essence - Self (default duration)
Has Smart - Cast Infuse Vital Essence - Self (modified duration - 4* seconds to take advantage of Smart)
No Smart - Cast Defense skill - Self (default duration)
Has Smart - Cast Defense Skill - Self (modified duration)
*combat happens around 4s intervals and this is to prevent a recovery period stalling refreshing VE.
You can also make copies of this for different levels (1, 5, 10, 15, 20) or gear/stat arrangement (WIZ/X 10 INT, WIZ/X 20 INT, WIZ/X 25 INT) so that fixing your delay times is just a matter of swapping the behavior to a different one.