Wow, There's a lot I want For KSP 2.
-more kinds of kerbals
-explosives to "terminate" rockets
-mod-ability
-Linux compatibility
-Better explosions
-More/bigger parts
-Weather (like dust storms, auroras, rain, and snow)
-the ability to make rockets on other planets by using a material system (like ore, or the stuff in extra planetary launchpads)