I agree. Look, for example, at his work on Logic, especially Categories, On Interpretation, and the Prior and Posterior Analytics.
Of course, the fields of Philosophical and Mathematical Logic have advanced since Aristotle, especially starting with the work of Frege, but that took approximately 2000 years. And before Aristotle, no work on Logic came close to what Aristotle discovered and developed. Aristotle's work on Logic was sui generis and hardly any advancement in logic occurred until Frege 2000 years later.
I feel his work in Logic alone makes him one of the greatest minds who ever lived. That doesn't take into account his contributions in other areas of philosophy, which were also significant.
Of course, the fields of Philosophical and Mathematical Logic have advanced since Aristotle, especially starting with the work of Frege, but that took approximately 2000 years. And before Aristotle, no work on Logic came close to what Aristotle discovered and developed. Aristotle's work on Logic was sui generis and hardly any advancement in logic occurred until Frege 2000 years later.
I feel his work in Logic alone makes him one of the greatest minds who ever lived. That doesn't take into account his contributions in other areas of philosophy, which were also significant.