The biggest issue i have with alot of premade kits is they do not consider "empty space". The new SOL kit with the plastic case that everything snaps onto is a big example. All that blank space of plastic for everything to snap into and fit into and look nice and clean and even on the ouside is wasted space for the size of the kit even wasting a "page" on the survival instructions for a pretty picture of a guys face and the magical title to imbue survival power to the owner. In the PSK I made off of the DR-PSP I attempt to put every rain drop sized pocket of space to use. Even the cotton batting I use to presse things together and keep things from rattling has a use when need be as a tinder.

So with that said I think that would be a great criteria to add. Space in the container they come in to expand and space wasted by fancy organization or containers. Quick tip get a caliper lol!