VADER 2008
Based on the evidence provided by the films, we can extrapolate the benefits of a Vader Presidency:
Total Commitment in the War on Terror - we can presume from the destruction of Alderaan, and the elimination of the Rebel base on Hoth, that Lord Vader would take an aggressive approach to terrorists. Terrorist bases would be totally destroyed, and the military might get to use those really cool Imperial walkers in the process. Captured terrorists could expect to have their veins shot up with truth serum by sinister looking droids. And no matter where Osama was hiding, Lord Vader could use the power of the Force to strangle him to death.
Smaller Government - at the beginning of Episode IV, we are informed that the Emperor has taken the bold step of eliminating the Senate, and thus a layer of expensive bureaucrats. Some people would pay real money to see the present United States Senate disbanded as blithely. Reduced Taxation - no one in the Galactic Empire is filling out forms for an Interstellar IRS, so far as can be seen. Besides, given Lord Vader's impatience in getting a Death Star built, he'd likely be so irritated by tax officers' incompetence, he'd strangle the lot.
Ethical Use of Biotechnology - biotechnology in a Vader administration would only likely be used to produce clone warriors rather than create replacement body parts: indeed, Lord Vader didn't create a clone of himself so that he could have his body parts replaced, thus indicating a higher level of ethics about cloning than has hitherto been seen from many scientists.
Strong Defence - the clone warriors would solve the problem of military recruitment, and furthermore, "Star Wars" research wouldn't stop until they'd developed a weapon to blow up a planet. As such, it's unlikely Middle Eastern terrorists would be inclined to mess with a President Vader.
It is clear that the benefits of a Vader Presidency outweigh the occasional "hostile takeover". It is also clear that few people in their right mind want to be President, as such, it may be time to draft someone who doesn't exist at all.