The good news is that "Who Framed Roger Rabbit?" stood up to the writer-brain test. In fact, I think I had a deeper appreciation of it this time than when I was a child. The plot was really well crafted and I loved the way the protagonist's backstory fit right into the overall mystery. However, the biggest reason for my glee was stellar worldbuilding.
The story is set during the 1940's in Los Angeles, and the environment is well set-up. However, this is a very special kind of alternate history. They didn't just put together a vision of 1940's L.A., but one in which cartoons were real people and creatures who acted in the cartoons as actors do in films, and had their own district, and had grown along with the town. The inception of different characters along this timeline was clear, and for example we meet Betty Boop, a black-and-white cartoon character who has ended up working as a waitress because she has a hard time finding work "since cartoons went to color." While the origins of the toons were left relatively mysterious (we know they were drawn but not how they got their life force or precisely who created Toontown etc)., they clearly have a life of their own.
They also have their own culture. They have different driving rules because neither the toons themselves nor the cartoon cars can be destroyed by having an accident - which is why Eddie Valiant doesn't want Roger driving his car. They have different kinds of expectations for the manners of others. Eddie does well in Toontown because he's familiar with the 'toons and their ways, as when he is being pursued, and rips the white line from the center of the road and directs it into the wall (thereby causing his pursuer to follow it and splat against said wall). Judge Doom is also familiar with cartoon ways (for his own reasons) and therefore has a failsafe way of discovering that a toon is hiding behind the walls in the bar: "the shave-and-a-haircut trick." Because he is a cartoon, Roger continues to follow his own rules even when he is outside Toontown, as when he slips out of the handcuffs that attach him to Eddie while Eddie is trying to saw them open. Eddie growls, "You mean you could have taken those off at any time?" and Roger replies, "Not any time. Only when it was funny." This really made me wonder if we were dealing with a physical law unique to cartoons, where Roger literally could not have extricated himself unless it was funny, or a cultural rule, where it would have been inappropriate for him to do so.
I was impressed again by the character of Jessica Rabbit, whose actions in the film lie right on a marvelous intersection point between strong-woman-character and cartoon culture. Modeled physically as she is between Veronica Lake (hair) and Vikki Dougan (the backless dress), she is in the ideal position to question sexist expectations. There's a reason why this scene is still well known, with its famous line, "I'm not bad, I'm just drawn that way." (it appears at 0:45 in the video below)
There is a lot more I could say, but these were the points that really stood out for me. If you enjoyed these observations, then it's highly likely you would also enjoy a rewatch of the movie. I welcome discussion in the comments.