I don't understand why you wouldn't want to be able to throw while in a vehicle. It's a very handy ability to have. I admit I don't often think about doing it but if you're chasing down an enemy and you're both in hummers you could toss your grenades and do a bit more damage to their vehicle. And since you can no longer use the vehicle to kill anyone {thank the game gods for Max getting rid of THAT nonsense} you can toss a grenade as you're passing by a group of enemies.
Anyway, that's my thought on it.
