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 and it should be removed as a power. How can a President ever decide that the entire legal process is flawed and their opinion is right? If the sentence was too long then change the sentencing guidelines.
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.
The idea has been around for a bit and I call it interesting, but also with huge potential of misuse.
Change the test slightly, so your target audience will yield better results, giving you a better result.
Either way, as long as climate change and darwinism are controversial topics, I see it hard to implement in a meaningful way.