>>150360368 (OP)
Obnoxious jew kid that has nothing to do with the based little babby he was. All that bravery, leadership, willing to push things, wanting to explore things, wanting to do the right thing all evaporated and he was left looking for a purpose, with no group dynamics whatsoever, which is the worst punishment you can give to a main character. And to counter that, they decided to dial his everything up and make him a hyperactive reject. As the other anon said, they truly did turn him into Stan Marsh.
Also, the whole show was just fucked as a concept, not necessarily just because the age-up, but because they made them 11 year olds, who looked and acted like high schoolers and looked like ugly klasky-csupo abominations. The artstyle that was a huge hit for babies and their vision of the world was absolutely horrendous for realistic teenagers. Their personalities also did not take the translation well, generic teen drama simply requires different archetypes. There is only so many times they could rehash Chuckie learning how to be brave or Angelica learning how not to be a cunt.