I very much love this idea!
I have 600 BP slots and its a pain most of the time if i want to find some sort of potion when i also have plants and resources in my BP + all the gear ofcourse.
Specialy recipes are hard to find because they can be learned at various different levels, some high lvl gear can be invented by a lvl5 player, and some cant.. if you don't know what level it can be learned, you can go past all your BP slots which is pretty anoying sometimes hehe
I have never used any folders btw, because i think its a waiste.
And i realy doubt there is loads of players out there that have massive upgrades in folders, or are there?