It was pretty mixed.
There were a lot of people that were upset about Walt leaving, but only really because no one knew anything about Mozeliak, and because WJ had been here for so long. Jocketty brought in a lot of big names to St.Louis, which brought a lot of respect from the fans, but people who followed the Cards' system as well as the big club could really see Walt's fatal flaw: a depleted farm system.
The Cardinals, under Walt, ALWAYS traded away a lot of prospects to bring in the big-name trade deadline guys (i.e. McGwire, Mulder, Rolen, Edmonds, Walker, etcetera). I don't know if Walt just didn't believe a strong farm system was a must when building an organization with some fiscal flexibility, or if he just felt those pieces were necessary, but he left a farm system that was always ranked near the bottom of the league.
So as a whole, I think a lot of us here were excited to see what Mozeliak could do, but we all respected Jocketty. I don't know exactly why Jocketty was fired, but I know there was a lot of divisiveness in the front office between WJ and Bill DeWitt. I guess the two just had different ideas on the future.