AZ SnakePit has more analysis of the reasons for the move, and what it might mean for the franchise going forward:
In the end, it comes down to Byrnes and Hinch having failed to put together a winning team on the field. The overall record under Josh Byrnes 4 1/2 year tenure as General Manager was a mediocre 349-378: while the team did win the National League West in 2007, it has been steadily downhill for the Diamondbacks since that 90-win season. If there was a watershed, I would have to say it was the signing of Eric Byrnes to a contract extension. It seems as if almost every major decision since then has turned round to bite the team in the ass, no matter how much they may have made sense at the time.
They also note that interim GM Jerry DiPoto, even if the position is temporary, still “has a crucial role to play, as the team decides whether to reload for 2011 or rebuild for 2012 and beyond.”