You're not interested in legal precedent, which you classify as "but he did it too," but here's one article on this:

From November 1993:

But if Clinton's most celebrated Cabinet member has personal integrity and a no-nonsense sort of flair, what else does she have? There is reason to believe that "the first woman to run the Justice Department" doesn't; the White House and Clinton crony Webster Hubbell share that distinction. Miss Reno's views on fighting crime, morever, hark back to the "root causes" rhetoric of the 1960s. And she presides over a department undergoing the sort of politicization Democrats used to attribute to Reagan-Bush Republicans.

Indeed, when confronted with what seems to have been White House pressure to buy time for Rostenkowski, Miss Reno didn't head for home, she fired every U.S. attorney, including the one investigating the powerful House Ways and Means chairman.

Normally, when control of the Administration changes from one party to the other, the old U.S. attorneys are replaced gradually. Thus, when Tom Corbett, chairman of the U.S.-attorney advisory committee, asked Miss Reno about the transition timetable on Thursday, March 18, and got no answers, he assumed there would be the traditional, slow handover. He reeled when, on Monday morning, Associate Attorney General Hubbell told him the attorneys would have to resign immediately. Literally. "[They] should be able to clear out of their offices over the weekend," one White House politico told Corbett. (Miss Reno was nowhere in sight.) Corbett had to fight just to get the attorneys an extra week to clear out.

The next day Miss Reno called for resignations. Jay Stephens, the U.S. attorney for Washington, D.C., resigned that afternoon, commenting that he had been within thirty days of a "critical decision" about Rostenkowski. (Once Stephens left, the transition lost its urgency; some Republican U.S. attorneys are still on board.) The Illinois congressman may yet be indicted for his alleged abuse of the House Bank, but Stephens's hasty dismissal surely slowed the investigation, leaving Rosty, who loses his chairmanship if indicted, in place to steer Clinton bills through the House.

I can help you out a bit, here. The Liberal Talking Point on this issue is that it's okay to fire attorneys for political reasons at the beginning of a term, but not in the middle.