OK, so he pardoned his buddies and a couple of rappers etc.
I think there's a good reason to allow pardons ba a president. It's a political tool, e.g. in order to avoid prosecution by an unfriendly successor, no matter who's the good guy and who's the bad guy. It's good for the time of passing power from one president to the next, else this process might not happen smoothly enough, e.g. because the current president might try to keep his power out of fear of the next one. If you want it to be a juristic tool, it should need approval by a court, but it doesn't. I think there's a good reason for that, even though people might be pardoned who deserve a prison sentence, one of reason of state which is sometimes a "greater good" than justice.
What remains is the impression it makes on the people. Just don't forget who was accused or convicted of what and got away with it like that.