Nope--don't miss her.
As much as I disliked her character--the writers didn't do the actress any favors in turning her into a duplicitous evil-doer where there was no previous discernable character build up to that effect. I gather that the writers just didn't quite know what to do with her character when she was "good," (if you want to call her that), but took the easy way out and made her into an almost laughable comic-book villain. (And at the same time, the writers certainly didn't do Vaughn any favors either in the Season Three. He recovered nicely in the Season Four, thanks heavens.) Therefore, there was no glimpse of Lauren in the Finale, but since Vaughn had "died," I guess there was no reason for a Lauren flashback.