The basic idea would simply be to add like an F3 command (F3 + R) that would simulate a world shut down and reopen without actually have to do that. It would make for much much faster scripting and resource pack editing.
Right now even on my system (Ryzen 5 1600, 1060 (6GB), 500GB SSD, and 32GB RAM), it takes nearly 30+ seconds to close down and reopen my world. This is greatly slowing down development. Just make 20 edits to my script or resource pack now loses me 5 minutes of actual work. Everyone knows how much you are going in and out of your editor and back into the game. So dynamic reloading would greatly speed up development!