You have plenty of small cases to choose from. Making another one would definitely not be a killer.C4 must not be other form of Ncase. You should add some killer feature like mAtx compatibility in smallest possible form like +10mm height to ncase, or be smaller. I totally do not like increase in size - better not to wait for C4 and buy right now ncase. No need to look for this oversized by marketing gpus if we have fantastic founders edition.
No riser (v4 now), Noctua D9, 2080-3080 founders in smallest possible form - thats a killer for me.
Just opinion.
For me a killer would be a sandwich case with two glass (not acrylic) panels and GOOD ventilation, which (with non-vented panels) means there must be room for one or two intake fans and two exhaust fans + 240/280 rad.