Would be nice if engineers could convert enemy vehicles as an option. Converting will add a symbol of the fuction to the vehicle. Adding it as an option between that and destroying the tank. Also, it will be only possible when ther is no one inside the vehicle.
I think it's been covered before. Devs said that there would be no vehicle highjacking in Empires. Not to say that I don't like this idea... In my version, this skill would belong to the Scout. He'd activate the skill and would be able to jack empty enemy vehicles (except the CV of course) by holding the "use" key for 10 seconds or so (much like Defuse works for Grenadiers). Hide would drop when the Scout is in process of stealing, and when he's done - the vehicle would simply belong to his team; no need to change the models or anything. That way the Scout would run the risk of being blown up by his own team if they get jumpy.