Why was season 2 of Steven Universe bad?
Two main things really made it bad. Horrible OOC characterization and mishandling of the plot.
For some reason characters like Pearl were completely rewritten to be infinitely worse. Pearl went from being a slightly neurotic and cautious to being rabidly selfish and having a psycho stalker crush on Rose Quartz out of nowhere. She’s went from caring about Steven’s wellbeing to willing to let him fall to his death simply because he happened to have learned about Rose’s armory before Pearl told him. And it’s never really brought up how bad this is.
Garnet stops being a character and simply exists to be Ruby and Sapphire. They push the LESBIAN angle so hard that it overshadows everything about her. Ruby and Sapphire start being the more important focus while Garnet herself became less and less of a character.
The plot kicked into high gear after the season 1 finale. And then….. we get filler. There are occasional Peridot episodes until she ultimately gets captured and brings in the Cluster plot. Which then gets pushed to the side with more filler. It got to the point I got sick of it and quit watching.
The writing is just abysmal. Sure there are some nice filler episodes but when there are big overarching stories you can’t ignore that for filler. And even when it does get to plot it’s extremely underwhelming like the Cluster being talked out of not being bad. The writers continually mishandled plot and relied on filler to be the backbone of the show with only occasional plot that does little but drip information in painfully small amounts.