MULTIPLAYER! ALIENS! WEAPONS! NUKES! FEMALE KERBALS! Seriously though, this game is in dire need of a physics update (new aerodynamics model as well as re-entry heat).
I'm pretty sure a modder can literally take all the current parts, and make a mod in which he rearranges them in the tech tree with different science costs. The user would have to remove all the original parts, and voila.