In ESB, Yoda lives on a world that is simply chock-full of all kinds of wildlife--both flora and fauna. Also in this movie Yoda tells Luke (regarding the Force), "Life creates it; makes it grow." How appropriate for the Jedi Master to live on a planet that is literally crawling with life. The antithesis of Dagobah, of course, is the Death Star (and, on a smaller scale, the Star Destroyers). These are completely artificial environments with no plant or animal life in evidence. They are the very illustration of the word "sterile". So where does Lucas have Yoda live in the PT? On a big sterile planet that looks more like the Death Star than anything else. Lucas should have had Yoda living on Dagobah in the PT. It would have been the perfect hermitic home for him. There the most promising of Jedi would go to be trained by the wisest Jedi Master of them all.