I think a major part of what makes Hazard such a fantastic player often goes unnoticed. It's the way his game influences the overall situation between the attacking and the defending team. A large part of what makes him so dangerous is his instinctive reading of the defending team's shape and the way he systematically reacts to their habits.
His off-the-ball movement, movement with the ball and passing are designed to counter the natural flow of the opposite team's defensive movement. So he constantly gives them headaches with his positioning and movements, frequently throwing them off balance as a unit. He then has a great timing for playing passes right when this unbalancing of the defensive structure has created openings. A lot of this happens before the final ball, which is why his statistical numbers aren't representative of his influence on Chelsea's game.
The way I see him, his game is 50% about this structural work (he constantly roams around and pops up all over the pitch during a game) and 50% about breakthroughs, assisting, scoring. He combines both aspects seamlessly and has a great balance between those elements.
But many people only see the latter 50% and that's where I think the impression comes from that he's 'not imposing himself on games enough'. In my view very few players (let alone forwards) impose themselves on their team's overall attacking game on a similar scale to Hazard. It's more subtle to the eye, but at the same time more influential on a fundamental level. Plus the spectacular stuff he regularly pulls off too, of course.
That's why I think he is one of the best players in the world.