The point is, no matter how great Hu is as an individual the danger is that granting him perpetual unquestioned power creates a precedent for a future monster to gain a similar lock on power. In a democracy, the voters can depose a monster peacefully. In the cureent Chinese system a monster would only get 2 terms. So the question is, are you prepared to accept Hu getting power to life, at the risk of a future person to get it being a Mugabe, or Gaddafi, or Amin?
In a system with very few constraints on absolute power, is it really prudent in the long term to remove all of the remaining ones? Finally, how much can you trust the judgement of someone willing to impose that risk on his country for his own benefit?
The problem with the CCP is that there is no real feedback loop. Their support is very fragile, and it would just take one recession to break it (they have no "lets throw the turkey's out" pressure valve).
My guess is that CCP is going to be popular and safe at the realm as long as growth is strong (so maybe we agree there).
People in China can only express their discontent by rioting (which happens in China, a lot). They have no other real way of communicating with officials, they can't even make sneaky jokes on the internet anymore to express their dissatisfaction. That alone is a very dangerous situation.
The Chinese communist obviously don't have a democratic mandate. But I think it would be a mistake to think that they don't have widespread popular support.