Shareholders are clearly pleased with Zynga’s move to replace outgoing CEO Mark Pincus with “games whisperer” Don Mattrick, who had overseen Microsoft’s Interactive Entertainment unit, which includes the popular Xbox business. Zynga shares jumped more than 10 percent Monday following the announcement, and the stock continued to make strong gains Tuesday.

Like Om Malik, though, I’m far from convinced Mattrick can address Zynga’s huge problems in expanding beyond the desktop to mobile. As I wrote a few weeks ago, mobile is a unique medium that has proved extremely difficult for game PC and console publishers to master. Small, pure-play game makers like Supercell and Rovio have made a fortune in mobile gaming, but the successes of established developers like EA have largely been due to IP licenses and extensions of familiar franchises from other platforms.

Mattrick doesn’t necessarily need to master mobile gaming for Zynga to turn things around, but he does need to find people who understand both the limitations and the potential of smartphones and tablets. Pincus was obviously unable to do that, and it’s far from clear that Mattrick can.