Hacking Monster Hunter 3U / 4U / XX plugins??

[s77uki]

Hii I'm looking for Monster Hunter (any of those 3 games) plugins or even ROM hacks that actually improve the experience by for example reducing the time for gathering points to respawn or increasing/reducing the time at the end of a mission or making small monsters respawn less/more frequently

Are these too difficult or even possible to make? Can I make them my self even though I have no idea how to do so? Or does it already exist?

Thanks in advance;)