I just finished the Japanese version of MediEvil, and from a technical standing, it's definitely the best version of the game. More/better cutscenes and animations, you can refill Lightning, some reworking of item placement and enemy behavior, some color changes, among others. Some of that stuff comes down to opinion, but overall, I feel it's the most polished version of the game. That being said, how difficult do you (those of you that have more skill than I do) think it would it be to replace the text and dialogue with that of the U.S. version? I know next to nothing about programming, so I'm not sure it'd be something I could do, but I'm very interested in the idea. I've seen patches for games like The Legend of Dragoon, where you can replace all of the English combat dialogue with the original Japanese, so I'm assuming it's not impossible, but again, I don't really know what I'm doing.
Edit: Extract all of the XA audio from the U.S. version as .WAV files. I can convert them back to .STR and get them in an XA folder, but I need to learn how to inject that back into the Image file itself. Luckily, even with them being in different languages, it's all set up exactly the same. For example, J4.STR  and E4.STR  both reference the same point in the game, meaning I *should* be able to insert English audio into the same places. Unless, of course, the time differences throw things off. Which they probably will. But it's a start I guess.
I already did most of what you said back in 2017, but in a less "redudant" way. First of all I directly imported the US version files and patched the executable, I also imported most of the text in the executables + in some overlays. Downside to importing English text is that you need to patch the font spacing, and you need to rescript all the dialogue of Dan, since those were removed. Oh, and you need to update all the text pointers. Here's some screens of the project, as you can see I also imported some old sprite data, such as the HUD. All the code I wrote for this translation project was in MIPS assembly.I stopped working on this project mainly because I didn't have much interest in it, and modifying some game stuff was an hassle since I didn't have a huge knowledge on the Engine compared to now.