The no body = no death point is a good one. Perhaps it just goes to Palpatine's overbearing hubris, that he doesn't worry about the fact that his "little green friend" (a dumb line, but McDiarmid somehow pulls it off) has survived. He may assume someone (it turns out to be Vader) will go on the great Jedi purge as needed after the fact; or just that Yoda is too small, in every sense of the word, to be a threat -- I mean, Palpatine has just transformed the Republic into the Empire in a stroke. What I like about that Ep III fight is that Yoda keeps fighting after it is clear he can't win -- it's got a kind of "fight the good fight even though it's hopeless" Lord of the Rings vibe to it. Plus, the symbolism of Palpatine literally dismantling the Senate (i.e., democracy) in order to fight is cool, if a bit heavy-handed.
The fight in "Ambush" is a lot more of Yoda using his brains in addition to his brawn, so maybe that is the difference.
I don't have many kind things to say about either Christensen or Portman's performance in Ep II, so I will just leave that be. Yes, he's supposed to be awkward and clunky, but Lucas' screenplay forces the development of that romance/creepy obsession so quickly -- Padme hasn't seen Anakin or thought about him in 10 years, and yet she falls for him just like that? Especially when he's gone all moody creepy crushing-from-afar for a decade, and she's not spooked by that? Oh, well, I said I would leave it alone!
