A number of games have been published or will be published that are similar to Bloodborne in spirit but aren't "true" sucessors - see Thymesia, Lies of P, or maybe even something like Blasphemous. Furthermore, discussions about how a sequel or prequel could look like have been had on YouTube, including bigger channels like Vaati, where concept arts have been created.
Based on all of this, how would the ideal sequel/prequel/successor/whatever to Bloodborne look like for you?
I like the idea of exploring ancient Pthumerian civilisation set way back before the happenings of Bloodborne. I imagine that setting could prove to be quite interesting both in its design and lore and could further expand the existing knowledge on Pthumerians, their culture, and maybe even their labyrinths.