Honestly, a constitutional amendment should be passed to strip the President of his/her pardon powers. It is a bizarre, monarch-style power which has the potential to cause a lot more harm than good. Or at the very least, pardons should have to be approved by a commission of legal experts.
Right... or at the very very least, stop presidential pardons from happening in the lame duck period. Or if you want to make it clearer what that is, just block all presidential pardons between November and January.
That's probably the biggest no-brainer of an amendment I can think of.