The reviews that give this episode as a masterpiece and rate it better than others that touch about the future or have a blind fanaticism to the character that I would not know how to explain, or simply did not really appreciate the chapters that are good and better than this in every way.
This episode tries to look like a spiritual sequel to Barthood, but all the magic of that other episode is lost in lousy jokes (if you laughed when Bart brought up Grandpa's status and still consider this episode better than Barthood, reassess your priorities when you watch again any other "future" episode) which hinder the plot and doesn't allow to develop the concept that they wanted, which to be honest looked interesting, but again, the writers nowadays do not come up with good writing when it comes to Lisa.
The only positive thing I give it is Lisa's design and the end of the chapter, otherwise, it's a total disappointment.