I'm guessing it's going to be a dynamic role rather than specific class. Like all vehicles spawn in, if you elect to jump in a vehicle you become a 'driver'. And you drop whatever class you spawned in as (e.g. only carry pistol). Vehicle drivers then become spawn points as well as squad leaders (for the entire platoon). Ideally this change will be positive.
It still allows those players who have a more strategic eye to still jump in the vehicles where air superiority/tank cover is needed. So it doesn't punish those who genuinely want to play the objective, just locks them into that role for the lifetime of their player or the vehicle per round.
It does stop people abandoning vehicles though, I'm not quite sure how this will work though. I don't think you should be 'locked' into the vehicle, maybe have a pistol only loadout to encourage those to stay in the vehicle, but if the drivers aren't locked in, it won't solve the abandonment issue.
Going to have to wait until the beta comes out or more information is revealed to make a proper judgement.