Although I've stated I prefer the new music, after watching it again, I think I have to change my position. The Ewok song reinforces the whole theme of Return of the Jedi, which is that if you have the will, nothing is impossible. The Ewoks had no technology or sophistication, but they had the will to bring down the empire's troops, and they did. Luke was horribly mismatched against the empire and Darth Vader, but overcame the challenge and made Vader see the light simply because of his willpower. The rebels did not have the army nor the supplies that would seem neccesary to beat the empire, but they were strong willed and defeated the empire nonetheless.

The Ewok song gives us one last reinforcment of this theme. The Ewoks song and thier celebration is low-key, just as thier assault was on the empire. But they overcome that and manage to have a great celebration.

And on a less metaphorical note, how would word have reached all those other star system's so fast. No one even witnissed the emporer's demise except Luke and the dead Vader.