Often when I see criticsm of Lisa as a character, the complaints are usually that she is a feminist lefty (she, like the show, has always been, just watch Lisa vs. Malibu stacy), that she is obnoxious and self righteous and finally that her plots often has her never getting what she wants and such but my problem is basically this:
https://deadhomersociety.wordpress.com/2015/01/16/how-lisa-simpson-became-her-own-substitute/
In recent seasons she has basically become a more sophisicated liberal version of Marge. She is so boring and over her age. Homer on the otherhand is basically a manchild. It wouldn't suprise me if a reboot would have Homer be a child and Bart's brother while Lisa is an adult married to Marge.
I think the real problem with Zombie Simpsons is the lack of balance. Yes make Lisa intellegant but also have her laugh at Itchy and scratchy with Bart, childishly obsess over Malibu stacey and mess around like a child would.