I suspect that was peak Ridiculous President Behaviour, tbh. Any future president that venal will take care to hide it a _little_ better.
And I think that was a little different; in that highly polarized environment it was possibly a little easier to sell corrupt pardons if they were of people on the president's 'team'; at least some of his supporters would put up with it on that basis. Holmes wouldn't qualify; she's just a generic wealthy criminal.
That's obviously no longer a constraint. The optics of pardoning Anthony Lewandowski (among many, many others) looked awful and he was still pardoned.