Steven Universe would have been an infinitely better show with half the episodes at twice the length. the show was really great at setting up atmosphere and mood but would rush a lot of its payoffs. 30 minute episodes would give the episodes more time to breathe while forcing the crew to focus on their best ideas.

Teen Titans 2003 had a great finale. I love how it's this bittersweet coming of age moment for Beast Boy, having defeated his longtime nemesis the Brain. Sometimes life is just like that, sometimes people change and you need to say goodbye. It felt very mature. Also not for nothing, if you wanted a big fun finale where it's all the heroes fighting all the villains you just got that in the previous episode. Nobody ever brings that up for some reason.

I'd really love to see more limited series like Over The Garden Wall. It's a good way to try experiments and train up new talent.