I am not quite sure what the deal is with Nueva Vía. I think the comparison to Blair and Schroeder is inappropriate. After Gonzalez lost his majority in parliament and until Zapatero gained the leadership (1993-2000) the PSOE was dominated internally by the conflict between Guerristas (traditional socialists, apparatchiks, barons, followers of then already former VP Alfonso Guerra) and Renovadores (renewers: third-way-ish centre left close to Gonzalez). Zapatero's nueva vía was in my opinion new with respect to this split.

Nueva Via was unheard of outside party circles before the leadership contest won by Zapatero, and has not been talked of since. Zapatero used other memes in his campaign to return PSOE to power.

A society committed to the notion that government is always bad will have bad government. And it doesn't have to be that way. — Paul Krugman

Just to confirm that the Barons are alive and well...

El Pais: The PM dines at La Moncloa with socialist barons (12-01-2006)

The appointment was at 20.30 at the Palacio de la Moncloa and called to it were the regional secretaries of PSOE and the presidents of autonomous governments, as well as the mayor of A Coruña, Francisco Vázquez, as presidente of the Spanish Federation of Municipalities and Provinces; the [PSOE's] Organization secretary, José Blanco, and the [party's] parliament spokesmen, Alfredo Pérez Rubalcaba and Joan Lerma.

A society committed to the notion that government is always bad will have bad government. And it doesn't have to be that way. — Paul Krugman