For all her success, Arianna Huffington is a notoriously difficult boss. Turnover at her Huffington Post has been high; it's mainly the young and hardy who last. So HuffPo's two new seasoned pros should produce either a surprising turnaround — or an all-too-predictable trainwreck.

Huffington has been on an impressive hiring tear. Her first coup was the April hiring of Jai Singh, who as the founding editor-in-chief of CNET transformed technology journalism with his hypercompetitive newsroom. At the Huffington Post, he'll be managing editor.

Now comes word HuffPo's investigative journalism fund, launched with a philanthropic grant of $1.75 million, has netted Washington Post investigations editor Lawrence Roberts as its leader.

It's easy to understand why high-ranking news editors are so attracted to Huffington's news operation. It performed admirably during the last election, roughly quadrupling traffic and making news with a pioneering citizen journalism project that caught Barack Obama making ill-advised comments about "bitter" working-class voters and Bill Clinton trashing a Vanity Fair writer.

And it has money at a time when other news media are in financial crisis, including charity grants and $25 million in venture capital investment.

But we can't help but worry about how this ends for Singh and Roberts. There's a reason Huffington has had trouble keeping past pros like the BBC's Elinor Shields — the last official managing editor — or like Rolling Stone's Frank Wilkinson. It's the same reason Huffington has instead surrounded herself with inexperienced twentysomething lieutenants like her godson Matt Palevesky, who took over the citizen journalism effort previously run by two seasoned pros, and severely-taxed New York editors Colin Sterling and Katherine Zalenski.

Or why Huffington only sought two years experience for the managing editor job before apparently stumbling across Roberts:

Huffington can be hell to work for. Those who have worked for her report she treats editors like personal servants, flies into rages, blends her professional and spiritual lives and brooks little dissent. And she must feel some pressure to reverse HuffPo's inevitable post-election traffic decline and to build up a sustainable base of advertisers.

But, as Huffington's spiritual guru would point out, people change. And perhaps Huffington has finally grown wary of micromanagement. We'll be keeping an eye on Singh and Roberts to find out if permanent adult supervision has finally arrived at HuffPo.