Touching on the topic of perfect parks... from what I know and have seen, I consider the following parks to be considered relatively "perfect":
Disneyland Park California
Tokyo Disneyland Park
Tokyo Disney Sea
80's EPCOT Center
EPCOT Center was excellent until the cartoon-ification began. It was excellent especially in the late 80's when Wonders of Life, Horizons, and Living Seas were all up and running... World of Motion and Journey into Imagination existed... and the park was distinctly adult in its intended audience.
If Disneyland Park had better maintenance and perhaps one more additional E-Ticket (the absence of Jungle Cruise & Splash Mountain is very apparent) it could probably be considered "perfect" as well. I wish I could consider Disney's Animal Kingdom to be perfect, and it almost could be... however, the lack of proper maintenance on Everest (along with its horrific back-view from the parking lot), as well as the horridness that is Chester & Hester's Dino-Rama, accounts for it not being put up there with the others. Magic Kingdom, plain and simple, is not perfect whatsoever. Compared to the Tokyo or California equivalents, it's not even comparable.
Now, as for Buzz - no, it does not "perfectly" fit in Tomorrowland. Right now, it "sort of" fits - which isn't enough, at least for me. Like I said earlier - get rid of the toy references, the ride suddenly works well because it's based in a sci-fi fantasy future... which is Tomorrowland's theme. Remove Fastpass, waits go down drastically, need for the attraction is reduced. Stitch has very little space for a new attraction, and Monsters is too new to be replaced... I suppose they could incorporate the Axiom Escape Pod sequence into the Stitch theaters, but I still think a dark ride in Buzz Lightyear's space would be incredible if given the proper budget & execution. And as for the idea of all future Pixar attractions going into Pixar Place - Wall*E fits better in Tomorrowland than Pixar Place. Monsters anything fits better in Pixar Place than Tomorrowland. Very clear distinction there.