Since the soulslike community is quite diverse, I can imagine many different opinions to emerge here. Curious to hear your thoughts!
I'd take Sekiro 2 any day of the week. Bloodborne 2 would be amazing, but Sekiro, to me, is the pinnacle of the genre and has so much untapped potential that's laying dormant. Bloodborne is too similar to your "standard" soulslike compared to Sekiro, even though I love Bloodborne as well.
Interesting points on the Sekiro ideas!
I suppose a viable approach for a Tomoe sequel could play into her real-life namesake? Tomoe Gozen lived several centuries prior to Sekiro's implied time period, but with the (possibly) historical person retiring from war to a life of Buddhist monasticism and the game character being involved with the search for immortality, I feel like someone more knowledgeable about Buddhism and Japanese folklore might have a good avenue to connect the two. A game playing as 12th-century Tomoe in a similarly-fantasticised Genpei War could work, yeah!