what is this "lack of a message" I keep hearing about?

The message is clear, except to those who would rule.

The message behind "Occupy Wall Street" is "regulate the bank$ters and hold them accountable for their crimes".

Krugman, indeed gets it:

...A weary cynicism, a belief that justice will never get served, has taken over much of our political debate — and, yes, I myself have sometimes succumbed. In the process, it has been easy to forget just how outrageous the story of our economic woes really is. So, in case you’ve forgotten, it was a play in three acts.

In the first act, bankers took advantage of deregulation to run wild (and pay themselves princely sums), inflating huge bubbles through reckless lending. In the second act, the bubbles burst — but bankers were bailed out by taxpayers, with remarkably few strings attached, even as ordinary workers continued to suffer the consequences of the bankers’ sins. And, in the third act, bankers showed their gratitude by turning on the people who had saved them, throwing their support — and the wealth they still possessed thanks to the bailouts — behind politicians who promised to keep their taxes low and dismantle the mild regulations erected in the aftermath of the crisis.

Given this history, how can you not applaud the protesters for finally taking a stand?

But we will keep hearing, over and over again, about the lack of message, until some of those who would rule us, Krugman's "malefactors of great wealth", are able to take control of it, like the Koch brothers took over the Tea Party.