Uninteresting missions aside, the game's biggest flaw, and one that is inexcusable, is its driving mechanics, which are, to put it simply -- broken. There isn't really a large selection of vehicles in Wheelman, so you'll soon find yourself switching between the same set of wheels. But strangely, the same vehicle seems to handle differently around every turn, so no matter how well you think you've mastered car handling, you can never throw your car around a corner and be confident of coming out of it the way you intend to. For a game that is so heavy on car chases, this is a major drawback.
One particularly horrific example of bad vehicle handling is a mission early in the game that involved Burik chasing down a guy on a mo-ped through markets and narrow alleys. It's a fun chase mission that is thoroughly ruined by the mo-ped's shocking handling, and even the sight of Vin Diesel riding around on a Vespa doesn't make up for it.
Pushing the left stick even slightly results in the mo-ped making an abrupt 90-degree turn, and more often than not causing you to crash into a wall. Now you could argue that a Vespa has a limited turning radius and would go out of control when sharp turns are attempted. But there's no place for such handling intricacies in a game that lets you perform melee attacks with your car.