The Jojo hat was changed because apparently some dude on 4Chan couldn't stand Valve profiting from "defying copyright" and sent an email to Erik.
Meanwhile, I've been having tons of fun playing the new divebombing Scout meta and having laser cannon fights with 5 other Engineers. But in terms of serious use, I think the new Short Circuit is in a good state. Yeah, you can delete a shit ton of projectiles with a single ball, but each ball uses a shit ton of metal, even if you're camping a dispenser. It's also fun to toss one onto the cart and hear all the delicious hitsounds.
...Also the Short Circuit's old alt-fire seems to not be entirely removed, but I don't think it'll be a major problem: