seedcake
I own only one pocket size deck and I can't imagine it can be smaller. I can use pocket as a reading deck and that's the important thing.
Please don't keep saying what companies SHOULD do. By all means say what you wish they would do.
If you want them to produce midi-sized decks - ask them. Lead them to this thread. But don't assume nobody wants minis.
MANY of us like to collect LoS pretty minis. You didn't ask which decks people wanted; this was a very broad-brush question about size in general - such questions don't allow for individual decks. There are plenty of threads where people say how lovely the (say) Ceccoli mini is.