Look, RPG Paper Maker is a great game engine, but not many people use it. The community is just tiny and when a problem arises, is next to impossible to find the right answer.
However, there's one way, and just one way, to make this software mainstream: add a proper sprite editor.
In the various versions of RPG Maker, fitting your custom characters into a properly sized sprite sheet is already a nightmare, which is why 90% of people who own the program use it to create games for their friends and family, reusing the anime-looking included assets. RPG Paper Maker is even worse in that respect. I've spent WAY too much time moving characters one pixel to the left and one pixel to the right just to avoid everything becoming a mess.
A lot of people loves to criticize GameMaker but the fact is that it's been around for more than 20 years, and several high-profile indie games have been made with it. One of the features that make it so popular is, precisely, the sprite editor. You can change your characters, objects or backgrounds without leaving the software window and see the results almost in real time.
You know all those little "experts" on Reddit who say that no game engine needs a pixel art editor because Photoshop is better anyway? Yeah. They're wrong. Absolutely wrong. That people can go to Hell.
Bitsy is extremely popular because, despite its simplicity, it provides everything you need in its quirky toolbox. The 8x8 pixel editor is an essential feature, not an afterthough.
Many people enjoy tinkering with RPG in a Box because it's a program designed to create simple 3D games and includes a voxel editor. If the program required you to "import" your own polygons, NO ONE would have downloaded it.
Even GDevelop has had to give in to community demands and include a version of Piskel integrated into its program, to make things easier.
Easy FPS Editor doesn't have a sprite editor, but it definitely doesn't need one: I can draw any crappy thing in Paint, and the program picks it up and re-interprets it perfectly in within seconds. The same can't be said for RPG Paper Maker.
So, in short, this is my advice: if you want RPG Paper Maker to become more popular, please, please, please, add a proper sprite editor to the engine. Thank you very much.