As Yoda is dying I believe he realizes that the ways of the Jedi have to change if they are to succeed in the new galaxy. He's seen the "end" of the Jedi as he knew it, and knows that for them to succeed in any shape or form in a galaxy post-Empire, they need to change. For proof of this I look to his quote to Luke, "Pass on what you have learned." That statement from Yoda marks a departure from Jedi teachings, in that Jedi are forbidden to love and to marry. I think Yoda knows that the Jedi have to adapt to have any chance at all. He could have instructed Luke only to scour the Galaxy looking for others who had a way with the force, but I think he knew that the old Jedi way had gone out the window when the Emperor took over. The weakness of the Jedi in noticing the growing threat of Palpatine as he took power was just one of the many things that Yoda probably saw as a weakness of the old order that could be corrected. Yoda's parting words to Luke also make me wonder if he had any regrets. I wonder if Yoda would have liked to have been part (as he came up) of a different Jedi order, one that would allow the bonds of love and family to form. If such connections had been allowed, perhaps Yoda, Obi-Wan and others may have lived differently. Regardless of how their lives would have been different, I don't think it is Anakin's love of Padme that brings him to the Dark Side, but his inability to deal with the concept of loss. The loss of his mother and the thought of losing Padme were what drove him, and I think that was indicative of him, not of love in general. Yoda must realize that, because he does not warn Luke of love or familial bonds. Both Luke and Leia grow up with an ability to deal with loss. Luke grows up thinking his father is dead, and upon witnessing the death of the only guardians he ever knew, his resolve is strengthened and he follows Obi-Wan. Obi-Wan's death leads him to harden his resolve to become a Jedi. Loss seems to drive Luke, rather than holding him back as it does his father. Leia grew up knowing her mother had died, and was early on thrown into the Alliance (knowing that she was always at risk). She witnessed the destruction of her home planet and it only made her that more determined to make sure the Death Star would be destroyed, and the Empire as well. I think that the Jedi (early on) should have encouraged love and taught those in their ranks how to handle loss. Anakin's love was not his downfall, but his problem with the loss of loved ones, and the fear of that loss led him to avenues he might not otherwise have traversed. Yoda's statement to Luke shows his realization, after all that had happened, that love was not bad for the Jedi to experience. Yoda, always perhaps the wisest character in all the Star Wars universe, understands that the Jedi have to adapt to survive, and that there need to be changes to the Order if it is to thrive again.