Sceptile Leaf Blade
Who would've found it more interesting if Jiren wasn't the actual final boss? Part of me hoped that it was Universe 4 that would be the final boss.
I would have loved that personally. Make Jiren a lot weaker and goofier and turn U11 into essentially the good guy versions of the Ginyu Force, and give the actual final boss to someone like Kefla or someone else entirely new but with personality. I just don't think Jiren has the emotional range to actually work as a final boss of a major arc, and with Ultra Instinct Goku also having no emotional range to be seen it becomes very stale. Kefla vs Goku was really well-received and cool partially because Kefla could actually carry the emotional requirements that such a role entails and was excited and invested in the fight. Yes, they say that Goku doesn't think about anything else than the fight and blabla, but they don't show it. Show, don't tell. There's no body language there whatsoever to show what these characters are going through.