Honestly, I've been seeing a lot of these crossovers lately, and they all kind of trip up on the same thing: the power systems don't mesh cleanly at all. 'Jujutsu Kaisen' runs on negative emotional energy and complex binding vows; quirks from 'My Hero Academia' are mostly biological, a weird lottery of genetics. When writers just smash them together, it usually feels lazy—like, Izuku suddenly has cursed energy because... reasons? The more interesting attempts I've seen treat the two systems as fundamentally incompatible forces. One story had Gojo showing up in the MHA world and being utterly baffled that their 'cursed energy' was so passive and didn't spawn actual curses; he treated quirks like a bizarre, harmless mutation. That created actual narrative tension instead of just stacking powers onto a character.
What works better, in my opinion, is focusing on the philosophical clash. Cursed techniques are deeply personal, tied to trauma and negative emotion. Quirks are presented as a tool for heroism, often divorced from the user's mental state. A fusion that digs into that difference—say, a jujutsu sorcerer horrified by pro heroes monetizing their abilities, or a hero student struggling to use a cursed technique that feeds on their despair—has way more potential. It's less about who can beat whom and more about the cultures crashing together. I tend to skip the ones that are just power-ranking exercises.