well if vehicles were added that would kind of ruin the game's point: survival. if you had something like a tank you'd be pretty much indestructible(unless your enemies all had fat men). You'd just kill all enemies with one hit, even if there were vertibirds. Now if it would be an-all vehicle dlc, then it might work, but only if all your enemies were vehicles themselves. but still, having an all-vehicle dlc would probably get repetitive fast. plus, it would probably get boring, because it would most likely be very linear and straighforward, with little to no exploration elements. if there's one thing i really like about fallout, it's exploration. that, and the story and role-playing elements :thumbsup:
Have you played Boarderlands? If so then you'd be able to see how they could make it work.
I think it would work fine if they had made that available in the full game instead of just putting it in a DLC. Unless they made some sort of racing DLC.