Here's a small mod that I made to fix the crappiness (low room / environment motive) of both trash pit (The Ash Grabber 5000) and outdoor bamboo toilet (Nature's Commode).
It goes into your Documents/downloads folder.

If your outdoor bamboo toilets are already crappy before using this mod, try selling and rebuying; or using the toilet once again.

As a side note, I've also tried fixing the crappiness of the "No Wild Movements" Outhouse but with no avail. It uses a global constant/behavior, so I cannot change it without affecting the indoor toilets as well.

Enjoy