Interesting posts but i dont think you can read too much into it though its fun to do so!!
I dont think much makes sense now because it was written in 3 very different stages, you can tell so by the way they have had to redo parts of the old films to make the new ones work. Even down to things like jango fett being father of storm troopers. This was made up later on (as you can tell from the voices being different till they were edited)
To say Vader was waiting for luke just doesnt make any sense. Especially since Luke is nowhere near the power of starkiller. He is a basic low trained jedi with very weak skills. Starkiller can destroy so much without a hair getting out of place.
To me in that way, Vader waiting for someone better than starkiller doesnt make sense.
I think the idea which fits best is that he never has any intention of using him.
The fact the emperor is not suprised when starkiller turns up at the end also says to me he may have been in on vaders "killing" him. Also Vader is utterly subservient to the emperor, this shows at the end of the 3rd film and in the newer star wars till he finds luke. Then i think its a father son bond which changes his mind. The realisation the emperor lied to him even about his children.
Love all the ideas here by the way.