It seems obvious that V. has more complicated interests than just governing a few wizards. In some stories, and sadly also in reality leaders fall into the notion that they have to unite the country under a strong hand to achieve anything useful. It might be that young V. thought so and tried to take over, but older V. is wiser and looks for other approaches. I don't think he wants Harry to become a dark lord, but shove him a bit into his own current goal system and avoid having him fall into stupid pitfalls.