I was watching "Clone Wars" Volume 2 this weekend and during the council's discussion about Anakin being promoted to Jedi there is an interesting talk about the Jedi Trials that were referenced in Ep I. The trials they mention are: The trial of the flesh, the trial of skill, and the mirror. Now alot of people look at Luke's training as being incomplete but he actually went through all of the Jedi Trials in Empire and Jedi;
Trial of Flesh- Loss of his hand on Bespin
Trial of Skill- The Battle with Vader on Bespin, Defeat of Vader on the 2nd Death Star
The Mirror- The cave on Dagobah
This also puts a totally different spin on why Yoda stated that Luke had to face Vader to complete his training. he wasn't being sent to kill him necessarily but to face his last test of skill. (obviosly Vader and Palpatine needed to be defeated but this was not the sole reason that Luke was sent to face them) What do you guys think?