My take is a bit different. I think that the current administration knows many, many things about the previous administration.........many damning things. The disclosure of such things (we can only guess how bad they are; what we already know is bad enough, we've all thought) could and probably would have profound repercussions in the political establishment, all over Washington, the defense industry, and maybe a fair number of foreign governments.
I believe the filth that occupied the White House for eight years had plenty of time (and zero morals) to compromise this country in unspeakable ways.
IOW, I don't think for a second that Bush is afraid of the Clintons. I do think he fears the impact of divulging all that they and their enablers did to this country. There is a huge difference.
For the record, I truly do not believe that this has a thing to do with his father's administration. That may sound naive, but I just don't think so.
Well, he handled Algore magnificently and easily when the Tree tried to intimidate him physically in one of the debates.
I think that Dubya doesn't want to spend his political capital in a rancorous, divisive, and inconclusive "investigation" into SickWillie's crimes.