Only in San Francisco would people complain about losing a $30/space parking lot.
Yes, I know it's better than nothing, but AT&T Park is served by more public transportation than just about any other ballpark in the country. There are Muni Metro streetcars and buses, BART, CalTrain, and ferries available. If you don't like pre-and post-game crowds on the bus, cool your heels at the 21st Amendment for a while.
Not that crowds are going to be a big problem for the Giants this year . . .