It's not about who deserves to be on the cover, it's about who they can get. Kevin Garnett is appearing on the NBA 2K9 cover, thus he cannot appear on the NBA Live 09 cover. LeBron James and Kobe Bryant would be ideal candidates except that they are too expensive.
But again, it's not about who deserves the cover, it's about who they can get to be on the cover. Dwight Howard cannot appear on the NBA Live 09 cover as he's signed on to appear on the NBA Ballers cover.
I don't see how putting Tony Parker on the cover is a wrong move anyway. Anyone with any sense at all isn't going to care about which player's on the cover; the discerning player is going to care about the game itself.