Lurker here! Hello all.
The X8 is great, but if you look at the open source ZX-UNO (which has been forked with a VGA version), you get everything the X8 has plus you get real game ports, 512K of SRAM, PS/2 port, and an expansion port!
It would probably be trivial to change the game ports on the UNO to SNES style controllers if that is what David wants.
To me the X8 feels like a design constrained by the skills of the FPGA designer - someone knows the X16 FPGA (I forget is it Xilinx? Lattice?) and that specific FPGA toolchain really well and is shoehorning the design into that FPGA when we could have all the things we want, memory, real ports, and expansion, going with a ZX-UNO forked solution.
And the cost would likely end up about the same.
I will buy an X8 as soon as it is released if David chooses to release it, but I will always be annoyed by the fact the design was unnecessarily constrained by the selection of the FPGA and there were plenty of templates that the X8 could have been built off of (ZX-UNO, etc.)