In journalism, we have a saying: Three makes a trend.

A few weeks ago, I ran into three different movers and shakers on our city streets. Each one first shared disillusionment over the usual suspects rumored to be running for mayor in 2015, and then expressed disgust with the current occupant of the office.

One's face twisted in disdain as he spat out the words: "The guy is irrelevant, and has been since the morning after his reelection." Another noted, "It took six years to build the Hoover Dam; six years in, this guy still can't figure out how to collect delinquent taxes."

All three had been, like me, huge Michael Nutter supporters. As I've explained to the mayor - whom I've known for years, and whom I like - he hasn't been a bad mayor. But my disappointment - like that of his erstwhile supporters - stems from the gulf between the mayor's image and what he's done.

We were promised a change agent, and we got a caretaker of the status quo. We expected a reformer, and we got a ward leader who was schooled in politics by backroom apparatchik Carol Campbell. We thought we were getting a CEO, and we instead got a micromanaging legislator by nature.

Now that the jockeying for his successor is upon us, I've spent the last few weeks conducting a de facto autopsy of the Nutter mayoralty, lest we get fooled again. Here are the three questions that should inform our consideration of candidates next time around:

Are You All Tree and No Forest? It's six years in, and the mayor has yet to tell us his vision for Philadelphia. In 2007, many of us thought that the councilman who led a march on City Hall in favor of continuing wage-tax cuts would be an urban New Democrat: an innovative, pro-growth progressive. Instead, we got five straight years of growth-crippling tax increases - in what was already the nation's highest-taxed city.

The mayor has consistently said he was dealt a bad hand when the economy tanked, yet he saw to it that arrests could continue to be made and the snow could still get plowed. Forget for a moment that leaders in New York, Boston, and Phoenix all used the recession to right-size their governments while still providing essential services; the fact is, Nutter's first budget came before the economic downturn, and it was a big-city tax-and-spend throwback, increasing spending by more than 3 percent. Meet the new boss; same as the old boss.

In the ensuing years, big issues were kicked down the road: union contracts, a frighteningly unfunded pension system, a mismanaged school system that was going broke.

Why not borrow from New York Mayor Mike Bloomberg and boldly take back control of our schools?

Why not be like Atlanta Mayor Kasim Reed, and march city workers into your office and walk them through pie charts that show the city's future in peril if something isn't ultimately done about municipal benefits?

Why not have an audacious plan - in writing - to recruit companies from New York to relocate here?

When, in 2011, I asked the mayor what he wanted his legacy to be, he replied: "Honesty in government."

That's laudable, but it's not a vision - it's a job requirement.

The mayor deserves credit for an enterprising sustainability policy. But, while greening the city plays well in Governing Magazine, he hasn't made the case for it at home. Perhaps because bike lanes seem like playing small ball when you're in charge of a city with the highest tax burden, poverty rate, and digital-divide numbers this side of Detroit.

Can You Get Over Yourself? In 2007, we elected an Urkel-like nerd, but then came the political version of The Nutty Professor. Our wonky geek got transformed into a cool guy - and Mayor Buddy Love didn't want the tough decisions of governing to spoil the good vibe.

Admittedly, this is just a theory. But it's one I first came to suspect during the 2008 Phillies parade, when the mayor was wearing a team jersey and clutching the World Series trophy in the float with the players. He seems to rap every time he sees an open mic (charming, at first), he giddily hung out with Jay-Z last year, and published reports have touched on his frequenting of bars in the wee hours, city-paid driver in tow. To be clear: I don't care what he does in his private life, but if your city-paid entourage is with you in a bar at 2 a.m., you're not exactly being private. That's when it becomes reasonable to ask: Don't you, like, have a city to run?

Do You Have the Guts to Lead? I didn't always agree with Ed Koch, but Neil Barsky's recent documentary about the legendary New York mayor is a reminder that a good mayor also demands being a city's coach: He hectors it to do better, appeals to its better angels, massages its fragile self-esteem, and, most of all, fights for it without regard to his own political future. No wonder Koch (or, for that matter, Rudy Giuliani) never attained higher office. A city is an amalgam of interests all fighting for their slice of an ever-dwindling pie; the mayor is the sole keeper of the collective interest, and a good one gets his hands dirty.

That means being willing to get people angry. A few weeks ago, the mayor was scheduled to speak at the groundbreaking of Oxford Mills, the apartment complex I've written about that offers discounted rent to Philadelphia's teachers. Because construction was done by a mix of union and nonunion workers, the building trades came out to protest, their ubiquitous giant inflatable rat in tow. Superintendent William R. Hite Jr. and Mayor Nutter were scheduled to speak. Hite did. The mayor saw the protesters and took off.

It was another missed opportunity to lead, in an administration full of them. Michael Nutter is an honorable and decent man, but the next time we pull the lever, let's make sure our guy has the guts to be who his political rhetoric tells us he is.

Larry Platt's column appears regularly

in Currents. He can be reached at larry.platt@gmail.com.