The point of commentary is to
A. Enhance my knowledge of what exactly is happening--explain various situations and why they are important and why the viewer should care (which thereby makes watching a match a better experience)
B. Make the game more exciting e.g. get hyped for intense situations and overall make the game feel bigger than it would feel if there was no commentary
The current auditions don't do that. A commentator, especially for something like Nationals or Worlds, needs to be passionate about whatever he/she is talking about, and most of the current auditions are monotone voices who merely repeat what the current state of the game is. Think about watching a sport--it would be far less entertaining without announcer, wouldn't it? A Pokémon commentator has to have that same kind of effect on a match.