Apparently, there is a spin-off version of AOT, which I had realized today. I watched all the episodes including the new one that came out today. It's funny and good, and I recommend AOT fans to definitely watch it. It has many easter eggs too http://gogoanime.tv/category/shingeki-kyojin-chuugakkou
It's honestly extremely difficult to explain all of the improvements they've made to the game since BBUv1 in plain text. It would be a lot to go over, so I would say just completely disregard any memories of BBUv1 and see BBO as an entirely new game, as if the previous version never existed. Then with that mindset, when you finally get a chance to play, you'll be able to point out all the differences.
The game overall is really good. It's so much fun because of the fast-paced tone of the gameplay, new mechanics and features like the Chat, the return of BBR-like simplicity in terms of content, and... honestly, again, it would be too much to go over if I was forced to explain it all in a simple response.
And don't just take my word for it, I've only see two fellow forumers completely bash it without seeing any positives. Only two, out of the entire forum's population, and when even the people you would least expect to like it actually see hope in it, that dang-sure says something about the game as a whole.
BBUv2 was essentially a more enjoyable BBG. It's kind of difficult to get adjusted to something different when what you had was better than what is the finished product. BBO is really just a BBG 2.9 update/overhaul but in the form of a new game. A lot of people don't realize this and alright with the way it turned out. I'm trying my best to get used to it but it just doesn't give me as much enjoyment as BBUv2. It could've been the new BBR.