I do think that we need more tabs in the FC chests so that we have more space to store items that should be freely used by anyone while still having space for items that are designated only to trust members. This is how I would set up my FC if I had more than a few members.
I'd say 6 tabs would be a good start. 2 tabs for junk/lowbie stuff, 2 tabs for gear/common crafting mats/materias and 2 tabs designated solely to trusted members only. Just my opinion, but I can dream XD