Yodas power is all about his size, like Luke in Empire you just dont expect someone that small to be that powerful. And thats also the point about his screentime, hes great in small doses. In Empire, the Dagobah scenes are great but Ive never once thought "I need more of this" - Im too busy thinking about giant space slugs and whether Han is going to cop off with the Princess. And that carries through to the prequels: theres just a bit too much of him. Treat him as an impact player, a super sub, and bring him on when you need a bit of little green magic, not two hours though, as I think Id just start to resent him.