I was just thinking about this last night.
I don't have much stash by the standards of some people on here, but I am already experiencing that feeling of "what will I ever use that for?". The thing is I like lots of contrast so even just buying FQs I end up with lots of leftovers, because I might only need a tiny piece and then I end up with lots of little bits that don't seem to quite go together. Rather than going to the trouble of finding a pattern that will work with those scraps, it is easier to just go out and buy more!
I guess kits are made for people like me, except I do not want to just make something someone else picked! For me if I am going to the trouble of handmaking something, I want it to be unique, so there is the kit option gone.
I think there is scope for more fabric swaps on here actually. I designed a little project for my sister's birthday and I was jsut thinking- great, I need about fifteen fabrics, but I only need two strips of each- how will I buy that without making it the most expensive pillow in the world?!!!