> 1) MAME's primary goal is emulating the system. For this we can ignore information > that has no effect on emulation requirements. In this sense all we theoretically need > for debugging is VBI data and 'images' where images are parts of the video data > consumers actually care about. AFAIK it doesn't even matter what the images are > because the emulated system didn't actually depend on the content of these images.
And here, yet again, you show your fundamental misunderstanding. MAME's primary goal is to document the hardware and preserve and document the software. Usable emulation is a nice side-effect, but it is very much not the primary goal.
Emulators like Daphne have playable emulation as their primary goal. That's why Daphne takes the easy route with conventional video files and auxiliary "frame files" containing additional data, including information the players/games get from the vertical blanking period.
If that was MAME's goal, we would have already gone down that path. We probably would have used pre-decrypted NeoGeo graphics ROMs, and kept the CPS2 XOR files. We also likely would've faded into irrelevance just like NeoRageX.