If it ever happens, my prediction of the first Yuri anime that can actually go popular mainstream will have ro be
- romcom or shounenish~ish (two popular mainstream genre)
- no Yuri bait that does not go through
- the main character actively in an established relationship by the end (in oppose to Nanoha and Madoka which were all gay as heck, but was never acknowledged as yuri)
- little angst, as ordinary people are not trained to handle Yuri angst
Which spark the question, which Yuri manga/ novel/ game have these characteristics? I think Spirits on the roof is a decent choice if they focus on romcom part. But any other idea?
Anime success is a pretty unpredictable thing. There isn't really a formula for it and sometimes things no one expected to sell become hits. We can't know if angst don't sell, for example, because there isn't a good example. I think Citrus and Netsuzou has as much chance of being a success as any other romance yuri out there.
I don't know what manga or anime would have more chance of being a hit. There isn't that much, tbh. Maybe Murcielago and Happy Sugar Life, as Japan loves their psycho girls. I think a Flowers adaptation has way more chance of selling than a Kindred Spirits one. The novel is already more popular and it reminds Maritime, that was popular on its time.
Actually, a better chance of a hit yuri anime would be an anime original. An Idol anime with canon yuri end for example would be the safest bet.
on the bright side if these soap yuri anime does not sell simply meant no more soap yuri for a while!! just make gamma anime dammit!
Actually, that will mean no more yuri anime for a while. Japanese producers will take it as "yuri doesn't sell" instead of "drama doesn't sell".
But if it fails to sell but still make the mangas more successful, there's a chance of more yuri animes from other publishers. Yaoi anime rarely sells, but they still make them because of that.