I would love to see JYPE debut an all-female band, with self-producing songwriters. I don't know if they've got any trainees with those skills, but I think it would be great differentiating factor from their current girl groups. They can be Day6's little sisters, and inherit the Wonder Girls' legacy. Probably not going to be very popular in the traditional sense, though... have to build their popularity step by step in the same way that Day6 and Stray Kids did, rather than the usual JYP girl group tradition of getting a massive hit within their first three songs. But it's an unlikely dream. (Also kinda depends on what kind of group gets formed out of LOUD.)
i think a girl band is unlikely. Even wonder girls were traditional idol group. i heard they learnt instruments during their Western promotions era. in their last comeback they did play instruments but not live on music shows if im right. FNC debuted AOA as half band/ half idol group but the band concept didn't work out and they became typical girlgroup. And FNC had many popular boy bands like cnblue and ftisland.
Bands may not be that popular anymore especially finance wise. if they may try a new concept i can see more a hiphop girl group with strong rappers and less dance based maybe. Like non idol hip hop groups that are popular in korea.
About self producing yeah i can see that happen like Stray kids; they may have members who can not just write lyrics; but compose and arrange too. Like Soyeon is really popular for that. Even SM the strictest company ever; allowed Giselle to write her own debut rap lyrics. karina said she is good in writing and she is learning producing too . Ningning already made her own self composed and written song for her graduation project. Although i doubt SM will let them do anything on group's albums; maybe they will get to be involved more on their solos.
And Taeyong and Seulgi just recently made a song "rose" outside of SM with both writing the lyrics and Taeyong i think composed it.