Adding additional cores of systems from other manufacturers to the Super Nt and Mega Sg just muddles the whole intent and design esthetic of these products. Leave all of those niche cores for the MiSTer.
We have had this debate before in this thread, but do not discount the popularity of Neo Geo and PC Engine/TG16, especially overseas. Ive noticed a lot more international customers buying the Mega Sg in Asia where PC Engine was king. A PC Engine FPGA would sell really well for Analogue.