The Jedis' whole continuity-of-governance plan sucks. They don't attempt to rally with the survivors, leaving the survivors to be hunted down and turned or killed by Vader (per EU). They don't attempt a third strike against the Emperor. They hide from the Rebellion almost as effectively as they hid from the Empire. They don't fight the propaganda war. They don't seem to have substantial caches of weapons or equipment. They don't attempt to create any new Jedi while waiting for Luke and Leia to grow up. They would've been seriously boned if Luke died in a T-16 accident or Leia was killed on one of her "mercy missions."

Their whole "going into exile" plan was probably based on religious, not pragmatic, reasons. To the Jedi mind, exile was probably the only thing that made sense at that point. Being raised in a fanatical order of super-powered warrior-monks must not develop much creative thinking.