There is no need for a new board form factor, because they have existed for many decades. Below the mini-ITX format with a GPU slot, there are 3 standard form

There is no need for a new board form factor, because they have existed for many decades. Below the mini-ITX format with a GPU slot, there are 3 standard form factors that are big enough for a full-featured personal computer that is more powerful than most laptops: nano-ITX (120 mm x 120 mm, for 5" by 5" cases; half the area of mini-ITX), 3.5" (from the size of the 3.5 inch HDDs, approximately the same area with nano-ITX, but rectangular instead of square) and the 4" x 4" NUC format introduced by Intel. With a nano-ITX or 3.5" board you can make a computer not bigger than 1 liter that can ensure a low noise even for a 65 W power dissipation for the CPU+iGPU and that can have a generous amount of peripheral ports, to cover all needs. Keeping the low noise condition, one could increase the maximum power-dissipation to 150 W for the CPU+iGPU in a somewhat bigger case, but certainly still smaller than 2.5 liter. I expect that we will see such mini-PCs with Strix Halo, the only question is whether their price would be low enough to make them worthwhile. The fabrication cost for Strix Halo must be lower than for a combo of CPU with discrete GPU, but the initial offerings with it attempt to make the customer pay more for the benefit of having a more compact system, which for many people will not be enough motivation to accept a higher price.