Yes I agree with all of the above.
However, I can live with the Luke and Leia are twins bit if only because it prompts my favourite scene in the trilogy:
VADER:
Your thoughts betray you.
Your feelings for them are strong.
Especially for... SISTER! So, you have a twin sister.
Your feelings have now betrayed her, too.
Obi-Wan was wise to hide her from me. Now his failure is complete.
If YOU will not turn to the dark side, then perhaps she WILL.
LUKE:
NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO!!!!!!!!!!!!!!!
And so begins the best part of the trilogy the destruction of Darth Vader and the redemption of Anakin Skywalker (as Sebastian Shaw [with hella-cool eyebrows]).