It shouldn't be that hard to merge most of the culture mods as soon as we (read: I) separate as much as possible into mod-specific files (rather than overwriting HIP files); especially swmh_landed_titles.txt is something that I need to do this for, but it requires quite a lot of work - will be very nice for everyone when it's done though.
I guess we could try to coordinate more when it comes to commonly used files (such as 00_cultures.txt). Doing that, as in perhaps having a merged version of that file (alongside our own ones), including more or less all changes from the submods, would be easier than fully merging the submods - which would take a lot of effort, both doing it in the first place and keeping it up to date.
More advanced cooperation than that seems unlikely.
I guess we could try to coordinate more when it comes to commonly used files (such as 00_cultures.txt). Doing that, as in perhaps having a merged version of that file (alongside our own ones), including more or less all changes from the submods, would be easier than fully merging the submods - which would take a lot of effort, both doing it in the first place and keeping it up to date.
More advanced cooperation than that seems unlikely.