The issue with that is, presidential pardons exist for a reason, as a solution to a problem, in part one of injustice and abuse of power of the legislative branch. Among a few other things, It’s purpose is a safety valve against unjust and cruel laws passed by a theoretically tyrannical or apathetic legislature.

It’s easy to look at this from the lens of “The President is corrupt and Congress is good” and so we decide to let Congress take the pardon power away, but then what happens when you have the inverse situation where Congress is corrupt but the president is good? Now the president has no power to protect genuinely innocent people from injustice.

This is what the American system of checks and balances is about. Every check is both a solution to corruption and a potential lever of corruption. The point is to split the power up so that while some corruption can happen, it’s the least likely to be able to become absolute. We cannot implicitly trust in the President, Congress, or the courts. And whenever there is a hard choice to make between “Punish innocent people” or “Allow the guilty to walk free”, the framers of the constitution erred on the side of the latter.

But ultimately, we do have other mechanisms to deal with this. Specifically impeachment (Which pardons cannot be granted for), and the ability for us to vote out the president, or a legislature that is enabling them. Also the president cannot pardon anyone for state crimes.

It’s a very messy, imperfect solution. But it has largely worked for 250 years.