TMBTM said:TPM yoda puppet was made to be a "younger" version of Yoda, that's why he is different. Of course for a 970 year old guy, you don't change that much in 10 years I believe!
But it's true that he don't look much younger after all, just different.
But you might change a bit living in a swamp for 25 years!! It's akin to an old human going downhill the last 3 years of their life.