It would be great if the various FPGA teams could agree common standards for Amiga enhancements. However MiST and FPGA Arcade were both started as Atari ST enthusiast projects IIRC. Both are building on the Minimig legacy but they are not as Amiga focused as the Natami team was and the Apollo Phoenix team is. Thomas Hirsch has been quiet for some time unless I missed something and I've no idea what plans Marcel has for an end product.
I know you put a lot of work in on your enhanced 68k ISA Matt and it must be frustrating that others have chosen a different path however I think it's a good thing that some enhancements will finally be available soon.