Luke's Training
In episode 3 Kenobi leaves Luke to his aunt and uncle as an infant. He knew that Luke was going to have Anakin's force potential, so why did he not start training Luke at the proper age, rather than wait until he and Yoda were so old that they were going to die in less than a decade? Then in ESB, Yoda is adamant about not training Luke until Kenobi convinces him otherwise, giving the excuse that Luke was too old to begin his training. Yoda knew as well as Kenobi that Luke had such strong potential, but he allowed Anakin's failure to dictate his choice about Luke's training.
So my question is, why were these two Jedi Masters, some of the wisest of the Council, so retarded when it came to training one of the only two who could possibly save the Jedi Order and end the oppressive reign of Sith and atone for Anakin's wrongs?