Only a handful of people in his Presidency have actually had their sentences commuted.
We would be better off if every one with a clean slate for ten or twenty years received a clean slate, than relying on the seemingly random pardon process to rehabilitate people who have already served their time.
It is also notable that:
Perhaps most significant for your audience, there is no indication that this president plans to use his pardon power in any systematic fashion to cut short prison sentences: the beneficiaries of his only two commutations were both old and sick and within six months of release in the ordinary course.
For a "Compassionate Conservative", our President doesn't seem to understand mercy very well.