Infodroid makes a great argument for the way the Yoda arrival should play out-- I know you're already on board. I would only add that the impact of Yoda's arrival depends on the danger we sense for the jedi. It has to feel truly over. I can admit that the first time I saw the movie, I had no idea Yoda was about to fly in. I didn't notice that the music wasn't carrying the day-- I just noticed I didn't really care about any of the jedi who were there to save Anakin.
If I cared, and I thought they were in danger, then the surprise of Yoda's arrival would have had real impact.