Democracy is the whole basis of our society. The lack of democracy is a root problem in our system. Increasing democracy will help us solve a host of other problems, including the apathy many people feel because they think they have no power over the system. There IS a democratic deficit in this country. A more democratic Canada will not be the same as this. There IS a tangible benefit from having more democratic institutions. Too much power is in the hands of one person, and we have to trust that he does not exercise that power capriciously or irresponsibly. Changing our institutions so that that is less likely to happen can only be to the benefit of the Canadian people.
Oh and I forgot. He not only controls the legislative and the executive, but he also appoints judges on the highest courts in the land including the Supreme Court. That means ONE PERSON controls legislative, executive, and judicial. How can you put up a wall within yourself to protect from the inevitable conflicts of interest which arise, no matter how well intentioned you are as Prime Minister?
He is criticized for being a micro-manager. However with all of this power, you pretty well have to be! More people sharing responsibility is a good thing!