But in any case, it's not true that no other emulators will be able to play it. DougRPG just showed the translation working on SNES9X with modification already. It would probably just take one small update to the official release.
There was about 4 years between the latest release of SNES9x (1.54) and the previous release, (1.53), and about 2 years between 1.53 and 1.52. Even if you somehow succeed with a timely SNES9x official release, that's still just 2 emulators and a single flavor nonetheless (there are many versions of SNES9x). Knowing this, I would have done it in a compatible manner so it works with the existing emulators. I like to reach as wide an audience as possible, and give people options with my releases. That's just me I guess. *shrug*
Byuu and LostTemplar did the right thing about the expansion. There is no secret here. The game only has 1MB of "cpu rom" so it was expanded to 2MB, and in the right way.
We can expand the SPC7110 data block too, and there is only one way to do that. And the expansion was needed because the new script size.
The existing mapping already allows for a meg expansion (half is accessible) that also works on the original cart and SNES9x already. It probably works on other emulators too, but I don't have notes on that. Do it however you'd like. No skin off my back. It's just a shame to have no way to run on real hardware nor run on any other official emulators when not necessary. So, I figured I'd offer another option.
Yes, but the problem here is the SPC7110. The expansion is very simple, like the expansion of any other game, but because we have the SPC7110 the emulators will need some patch. Snes9x for example checks for the SPC7110 and uses a custom map if it's found, so we don't have control to make it to work, so we need to release a new version.
As mentioned, the existing SNES9x already maps the additional free space that is also compatible with the real cart adding two wires. 90-9f:8000-FFFF.
I have asked Ikari the person who makes the firmware for the SD2SNES about this game if it will be supported. Funny enough the real time clock the sd2snes uses is based on the code for the spc7110. So yeah support for this game on sd2snes is pretty much guaranteed.
While Ikari did a great thing with designing the SD2SNES, unfortunately he has not been able to add any new special chip support in the past several years. SuperFX for instance has been in progress for years now. I don't see adding the SPC7110 decompression engine in the foreseeable future. Hopefully I'm wrong though.