So like having hashtags in your profile, you could include ban-lists there, and your preferences would be calculated (and people could see what your filters were).
Yes, this wouldn't solve the issue of filter bubbles but the Twitter's algorithms could augment how to weight people's ban-lists with actual mentions/RTs - so I would see someone on only one of my ban-lists but got a lot of RTs/mentions I'd see it. If I find I'm not seeing stuff I should, I could alter my lists