What can you say about a top manager who is so blinded by the past that he can’t see the future?

That pretty much sums up Yahoo CEO Jerry Yang. He finally decided to step down late Monday, “ending a brief, turbulent tenure,” according to the San Francisco Chronicle, “that was marked by a slumping business and a failed takeover bid by Microsoft Corp.”

That pretty much covers Yang’s 17-month tenure as CEO, but it fails to fully capture just how badly he did leading the company he founded, and how inconsistently he managed his most important resource—his human capital. Here are a few highlights:

• Yang single-handedly blocked an offer from Microsoft to buy Yahoo at $33 per share, or more than three times what the stock traded at Monday. A key component of his push to block the deal was his unprecedented decision to offer a lucrative severance package to every single Yahoo employee in an attempt to make the deal too expensive for Microsoft to pursue. My take at the time: If Yang and Yahoo had applied that kind of creativity to its ongoing business, maybe it would never have had to defend itself against Microsoft in the first place.

• He brought in highly paid consultants to handle what every person with half a brain who was watching the company knew—that Yahoo needed to cut its workforce. My take at the time: Yang doesn’t have the managerial huevos to do the tough stuff that comes with a management role.

• Yang was indecisive and unable to make timely decisions at a time when Yahoo was under extreme pressure to act quickly and show positive movement. My take at the time: Yang’s indecisiveness is absolutely a killer in Silicon Valley, where rapid decision-making on “Internet time” is a critical competitive advantage.

To be fair to Yang, he should have never, ever been put back in charge of the company he founded. That’s the failure of a desperate Yahoo board of directors, because all Yang’s tenure has done is make Yahoo’s situation a whole lot worse. That Yang didn’t see this sooner and depart earlier was part of his problem. He didn’t have enough managerial experience to see the writing on the wall and know when to get out.

As CNBC’s Jim Goldman put it, “Clouded by self-interest, [Yang] lost his way, sacrificed tens of billions of dollars in shareholder equity, abandoned reason, and surrounded himself with people who slapped him on the back, or gave each other high fives when Microsoft pushed back from the table, depending upon who you believe, for a job well done. … The stunner is that it took this long to get him out. The stunner is that the board gave him such an amazing amount of latitude to leaf-blow his way through so much shareholder value.”

Yang will now go back to his job as “Chief Yahoo, a nebulous position that will allow him to keep his fingers in a number of projects but has no day-to-day management responsibilities. He will also remain on the company’s board,” according to the San Francisco Chronicle.

That’s probably an appropriate place for a guy who founded the company, but if I were the Yahoo board, I’d keep Yang away from anything resembling a management duty. He’s shown time and time again that despite his technical expertise, he doesn’t have a managerial bone in his body. Getting rid of him now falls into the category of “better late than never,” but it remains to be seen if Yahoo, and its beaten-down workforce, can rebound from bad managerial mojo its overmatched chief yahoo left at the company’s doorstep.