DP was ranked #5 when Conor beat him. If you do not think that is worthy of a shot, it is quite clear that his current streak + the manner in which he has won = better than anyone else in the division right now. To argue otherwise is to engage in mental gymnastics.
McGregor seems to be the more fluid striker, has better movement, and - without question - has cleaner, faster, and more powerful hands relative to Aldo. Aldo, on paper, appears to be the better grappler, indeed, but to say that Aldo is "much better" on the feet seems off-base.
No one is more dangerous - from a number's perspective - than Conor right now. Even when you compare the early parts of their respective careers, Conor was/is more dangerous than Aldo.