It is odd that the shield being down wasn't made clearer (or if it was even the case) after the bad guys boasted about it and Anakin's entry is the key factor that saves the day.
I personally had less of a problem with Anakin getting into the shield than with him meeting zero resistance when he got there. Sure, there were droids that were essentially useless. Where were the turrets? Where were the other fighters?
Further, why did the hanger bay lead directly to the reactor, or something that could be shot that would lead to the destruction of the entire ship. That makes the lack of security look even more silly.
Sure, the Death Star designers had the exhaust vent that could set off a chain reaction and destroy the station. But the rebels had to steal highly guarded plans to find out about that. The Empire clearly had no idea it existed (Tarkin and Vader said as much when they were wondering of the Rebels found a weakness). That's bad, but not nearly as bad as having a hanger bay lead to the reactor, protected by only a single shield that is periodically lowered!
But my point is that the Yoda/Palp fight was not a plot necessity. They could have left it out of the film and it would not have made any difference, because Yoda is thematically not a character in this movie, and would not have been included if we didnt know him from the OT.
I have to agree. In fact, the battle was so unnecessary that I didn't even remember it until it was mentioned here.