Optimizations to the entire client so that modpacks don't have troubles.
Could you specify a few of the troubles you experienced that the modpacks encounter?
Like faster and more lightweight launcher just if you need to restart the game and then the launcher will be there without decreasing performance.
The client isn't going to be the same as the current one and the client doesn't have any relation to how well a game runs. You can just close it after you launch whatever game you want to play, even now.
You won't be notified about changes to this idea.