Gonna have to point out that at least in the US, 6 stuff packs is $60 ($10 each) and an expansion pack is currently $40, so an extra $20USD for everything that comes in the current pack.
Good for EA, not so good for the completionist player.
I'm also not sure that a Stuff Pack that's more Sytems than Stuff (most of your pack suggestions appear to fall into this) would be particularly well recieved. People still ding the Bust the Dust Kit because it only has 5 non-debug items in it, even though it also has the dust system itself and two aspirations, never mind that it was buggy as all get out when it released. (I don't own it because I don't enjoy chores in my Pretendy Fun Times)
Besides that, my understanding of how labor and budget is allocated at EA/Maxis is that it depends on the size of the pack. While some developers have a knack for getting more into a pack than the budget would seem to allow for (see: Paranormal Stuff, Nifty Knitting, arguably Life and Death) this seems to be an exception rather than the norm. So a pack that focused on giving us a world and everything needed to build in/create sims from that world probably wouldn't have much in terms of even rabbit hole explorations, because writing those does take time. (and if anyone suggests AI for this - Maxis has enough problems with quality control, we don't need sloppy AI added to the mix)