Compared to other issues raised so far in this thread, crying for kewl animationz seems a bit dumb.
While you can't get more realistic than spaceships, laser guns, and lightsabers to begin with, stuff like this can have serious ramifications in gameplay. With one-shot kills in an RPG, all you'll do is force the player to reload much more often.
a. Sith Lord/Jedi Lord wouldn't be a special class; they're titles that, in the context of a game, are attained from reaching a high enough level to kick everybody else's ass.
b. Prestige classes suck.
Considering that you were desperate for realism, this is extremely odd, to say the least. "Buying a feat point" is representative of your character practicing and learning that particular feat. You can't just make your character "un-know" something and subsequently instantly know something else.
If you want to hop around like a mexican jumping bean, take some PCP and take a flying leap off a tall building. This is utterly ridiculous.