Someone might have already pointed it out but for me, the sentence of RA is not the main issue, the issue is allowing a single person to stamp through an entire legal system and undermine all of the time and money that is invested in it, even if that person is a president. I suspect that the idea originally was to give some safety valve but if it is used more than a few times by a President, it makes a mockery of it…
On its own it is not that bad an idea for someone who carries a mandate of the majority of the population to be able to grant pardons.