Still going to be seen by a very large segment of the population as using his power to humiliate a vanquished rival.
How about an off the wall idea? Instead of the FBI investigating - have Congress ask a truly neutral and respected third party to do so. The Rangers (everyone respects them, they have the ability to investigate, few jurisdictional problems), JAG (ditto), hell, even the Mounties if you don't mind going across the border ....
Half the population was boo-hooing all over the web and blowing snot over her losing. Wah. Considering voter turnout nationwide was pretty low, that isn't as large a group as 51% of the population, not even half of the voting public.
The investigation was in progress and had been in progress long before DT came on the scene as a candidate. It should be pursued, regardless. If that melts the snowflakes, let us know and we can all get waders.
If the investigation will involve classified material, you will need people who have clearance.
Obviously, current ranking DOJ is tainted, and are possibly unindicted co-conspirators to resurrect a term which should be familiar to all who recall her from before. I think there is a cadre involving DOJ, the White House, DHS, and other agencies to make sure that everyone had everyone's back covered, and they were all engaged out of ideology or profit.
Short of cutting the heads off a medusa of snakes, any investigation will snag someone with a conflict of interest. Even the investigators who quailed or balked in the face of likely reprisals, overt or otherwise when there was a possibility she would be POTUS are tainted and open to subsequent charges of misfeasance or incompetence when a subsequent re-investigation reveals things which should have been more obvious.
It's a quagmire.
However, a Pardon??? Not only no, but hell no.
Just because it is difficult to investigate her is no reason to let her off. The convoluted nature of the secret selling and influence peddling conspiracy in our government should not be the excuse to let this treason prosper. That would be a very dangerous precedent to establish indeed. Nor should the past 'wink-wink' attitude toward buying political access be invoked when that is very likely what has been done here on a much larger scale.
Virtually everything the Clintons have done in the past has been dirty local politics writ large and larger, now performed on an international scale rather than a smoke filled room after a county commissioner meeting.
But here's another question. Did DT himself buy access with his donations or otherwise and would that serve as reason to put a damper on the digging?