Yet Yoda and Obi-Wan do not consider the possibility that Luke may be right. And this again shows the inherent weakness of the Jedi. I don't see them allowing Luke to go fight Vader in "Empire" a repudiation of "old school" Jedi thinking; freedom of choice (even if it's just lip service) and a reluctance to "interfere" with an uncertain future are certainly elements of the warrior-monk philosophy that we saw from the Jedi in the prequels. Mace Windu and the Council were perfectly content to sit idly by and watch events unfold until it was too late to do anything about them.In his fight with Palpatine at the Senate, Yoda realizes pretty much what Warmark Jay said. He realize that the Sith had changed and become more powerful, and that the Jedi had remained unchanged and complacent. He realizes that the Jedi must change as an order.
In a sense, this story is not a struggle between good and evil - it's a struggle between "immorality" (the Sith, whose exploits speak for themselves), and a type of "amorality" shown by the Jedi. For whatever reason (fear of their own power?), the Jedi were content to be just what they were - the guardians of the Old Republic. And like any watchdog, they obeyed they masters without giving much thought to the consequences. The Jedi used their powers to preserve the status quo, not for any ultimate good.
Wow - a "Star Wars" movie that inspires deep thought. Go figure.