Yes, I do have a justification for the dark thatch roofing. Thatch is only that yellowish colour when it is new, and realistically, not every single one of these houses is going to have a freshly thatched roof at the exact same moment. So I have decided to use dark thatch to represent houses that have seen more years.
I've always interpreted the light vs. dark thatch variation as representing differences in materials - dried straw and rushes used for thatching tends to be a bit lighter than reeds and sedges, AFAIK. Aside from that, we have the two variants because they tend to work well respectively with the lighter palettes of the southern regions, and the darker palettes of the northern regions.
Using different colors to show aging is an interesting idea, but I'm not really sure it works well without a range of thatch colors from 'fresh' to 'aged' to 'moldy and overgrown' (unfortunately not something we can really implement at this stage). Keep in mind that thatch rooves would be regularly added to with a "spar coating" as well, so although some thatch rooves might be older than others, it probably wouldn't end up as extreme as the difference between the light and dark thatch blocks appears. Also, using dark thatch to represent older thatch rooves would mean that we'd realistically have to follow the same logic everywhere that currently uses only light thatch.
Other than that, I'm not necessarily opposed to some vernacular architecture, but I'm adamant that we try to plan styles on a regional or subregional basis (using shared cultures, geography, etc. as a standard) and have some degree of cohesion between projects, rather than every project trying to do its own thing and have a unique style (to the extent that project borders are somewhat arbitrary with respect to cultural and geographical regions). I'm just having a hard time currently seeing where some aspects of the style fit with the surrounding projects (Ambrose, New Barrel, and Bitterbridge to the south, and Hamell and Peckledon to the north), or what cultural/geographical factors would cause the Varner style to differ so significantly from its neighbors.
