This is not a screenshot but a fragment of the map of 4-2. Some tiles were redesigned so more background detail could be added.
...
It still plays the same as before, it just looks a bit different. No more big empty spaces.
That looks so much better! Excellent work!

What would help more than just the basic map import stuff is to have an option to import a file that contains both the tile index and the palette index at once rather than having to #incbin a map and #inctile/#inctile_ex the tileset... just have one single #incmyawesomemapfileyo or waddat that contains both the palette index and the tile index, so that way the same tile in VRAM could be used with multiple palettes. But alas, no such fun stuff. *sadface*
You can already do stuff like that just by creating/using a separate conversion step, and some custom assembly-language code, and just #incbin the resulting data.
I could be wrong, but I thought that Arkhan was already doing that in his projects.
HuC itself can also be improved, there's nothing magical about it ... but people have to actually be willing to push-the-envelope and use new tools in order for it to be worth some third-party spending their time to make improvements.
Now is absolutely the wrong time to do that for Henshin Engine, you guys are far-too-far along.
But when/if you start the next project ... that's something for you all to think about.