Tack said:

So, a moral problem I've been wondering about: WOULD Luke have gone back to Yoda? Think about it. He clearly feels betrayed by Yoda and Ben at the end of ESB, so the question is, would he have gone back? Or would he simply feel too betrayed to go back?

I'd say Luke is more confused and conflicted than betrayed at the end of Empire. He's not sure that what Vader has told him is the truth. Yoda and Ben obviously know what's up so he would be crazy to not go to them and find the answers, where he will learn that Vader is the only one not lying to him. It's the conversations with Yoda and Ben in ROTJ that leave Luke feeling betrayed. This is a point I think the film should have hit harder on. Luke's mentors have twisted the facts in order to get him to do something he otherwise may have went against. This would be weighing heavily on Lukes mind as he is hiding in the shadows from Vader and a good reason for him to turn against his former allies and make a new father/son team with dear ol' dad.