You should make a separate category for those damned rocks and environment big terrain objects such as the pillars in caverns pieaces of road big rocks and rocks in general, that would be a big but quite useful and specific category, then you could move on to continue to categorize your sized categories with much more ease since the lists should be significantly shorter the other category you should add would be a signs category which if you want could be subdivided in megaton signs, lamplight signs, wasteland signs, metro tunnel signs, and most importantly a panoramic sign category like those of the corvega and vault ones . for the big, really big and extremely big categories make a separate house or house front category. and i think this might be a small category but quite useful a lamp and light source category. i know it-s hell of a job but you asked for feedback and suggestions and i think this might help