Yeah, I gotta agree. I'm an 'old guy' now (over 50) and I loved a lot of Ralph Bakshi's earlier work, but even at the time this was just a chore to wade through. I do remember loving a bunch of the transformations (I'd have had no problem with the world turning 'full cartoon' forever), as well as puzzling out the strange variations in Holli's own changes. When she's returning to cartoon form the first time, she doesn't turn into the same 'Holli Would' she had been. Instead, she keeps turning into a silly, clownish cartoon with heavy makeup, a huge beehive hairdo, big 'puffy' gloves and enormous clown shoes. For example, skip ahead to the 1:00 mark of this clip...
https://youtu.be/rhFw9HYTReY Eventually I figured that the transformation into a 'doodle' made someone a parody of the person they were at THAT specific moment. Thus, then she was making a fool of herself on stage in front of a bunch of lustful men, she was not turning back into the 'doodle' she had been originally, but was instead turning into a completely different 'doodle' - a hyper-sexualized clown. If she'd returned to Cool World right then, she might have 'reset' to her new form and remained a clown. It's only through killing Brad Pitt later that she returns to her original form, because murder is a more 'serious' business.