Server side performance and mod integration

I run a small mc server and would like to see the game utlize multi-core processors better. Also, I think that as Minecraft grows, it shouldn't just be in a straight line. As more features get added, those who don't like those features take a performance/bloat hit (bloat meaning that the game is flooded with things that it doesn't necessarily need). However, to fix this, I think the vanilla launcher should feature different mods/modpacks that are very simple to add and remove. While you can definitely add mods as the game is right now, I know a lot of people who struggle with it and as mods get added, performance tends to take a massive hit. I think the game should move into branches instead of just moving linearly. Different pieces can be added and removed tending to the player's taste.