"He is reckless"
"So was I, if you remember"
obi wan is obviously referring to the time before he became a jedi. "Was I any different when your first taught me"
"I thought I could train him as well as Yoda, I was wrong"
it's never revealed in the OT why Vader turned. doesn't indicate that obiwan did anything suspicious, just that he couldn't get anakin to stick to the jedi gameplan.
"Do not underestimate the power of the Emperor"
yoda is warning luke about the emperor's power, that's it. either his brute power or his powers of seduction. I fail to see how it indicts yoda or the jedi.
They can be at peace and still be flawed
The Jedi in the PT are more than just flawed. They are blind, arrogant and lack compassion. They are a far cry from the noble and proud order the OT had made them out to be.