The whole concept of “The Republic” lasting even over a thousand years at peace is frankly ridiculous at an intergalactic setting. There are so many people, so many ideologies, so many changes to culture with such scale. I could buy it if the Republic has fought a large-scale conflict every hundred years or so, resetting the public consciousness in favor of the government, but even then “a thousand generations” is all too silly.
I’d agree to see a younger Yoda could backfire, but if keep him one of many other characters it should work. He might never be in danger but those around him will. Yoda has never revealed much about his past, so anyone besides him in this new era can be killed.