Emeralds are rare? They're the easiest to get after iron, most people playing a lot have practically infinite emeralds. Why do you think better gear is necessary?
I agree it would be more interesting to make non-diamond/netherite armor actually have a use but I don't see a need for Mojang to get into it. The armor is perfectly fine as-is for the sandbox game Minecraft is and if people want it to be more MMO-like and have more interesting gear or mobs or anything plenty of mods have been created.
Revamping The End and adding some sort of ore there would be cool and interesting, but I don't think better gear is necessary at all. There's already mods and plenty of servers with custom items if you want that, and what more would you want in the base game than netherite?
Better than diamond in durability and looks, also "you can make armor and tools with it, but that's it" you could turn it into blocks and build with it if you like :D
I didn't think there were really PC gamers these days who didn't use Discord, we do have our own forums but they're pretty much completely inactive now due to Discord being used.