I have to agree somewhat w/ Darth Nigel but for a different reason. Through the failure of training Anakin, and the other Jedi of the time who went off and joined Dooku, Obi-Wan & Yoda realized there were certain flaws w/ the way the Jedi were trained. The most being emotional/parental attachment. During the time of the Old Republic, once the Jedi recognized an infant of having a high midochlorian count, they wisked them away from their parents, who they would never see. However, I think Yoda and Ben realize that this was a mistake, and there is the need for the parental connection. This parental was also key, as it was the only way Luke was able to survive his encounter w/ the Emperor and bring back Anakin. Also I think the wanted time to pass for both Luke to gain a certain maturity. Yeah he was complaining about not being able to go to Tosche and buy power converters, but so would any 20 yr old. Plus Obi had to not use the force in order not to give off a feeling and remain in seclusion.