LP,
Autocracy is the least likely to be taken over by elites, in which case it is no longer an autocracy. The only way to maintain an autocracy, and thus a government of stewardship, is for autocrats to be capable. Thus you need them to be selected by merit. Merit, of course, implies intelligence and hard work.
You may think that meritocratic selection will not work because it is unnatural, however it worked incredibly well in Rome under the period of the 5 good emperors. The emperor's power eventually passed on to Marcus Aurelius' son, but the circumstances in which that happened is more complicated than "Oh, Aurelius was just too sentimental about his son inheriting the throne."
The issue of government I am addressing is elites. My point is that representative government is the government of choice for a commercial elite. If I am wrong, then why is it that there is a huge correlation, both ancient, medieval and modern, between the emergence of a commercial elite and representative government? And furthermore, why do these representative governments tend to favor commercial interests the most? My second point is that political stewardship is short lived under such a system, and the best way to ensure stewardship is to establish an autocracy. Of course, you are welcome to counter my last point with reforms that you believe will limit elite influence and promote stewardship, but my knowledge of history gives me zero confidence in representative government being one of stewardship. If you want to counter my first point, then that is fine, but I believe it is my strongest point.