You need only glance at the furore surrounding the new home of the Scottish Parliament to understand how architectural reputations can be transformed during the building process. It is less common for them to be turned around in the duration of an exhibition. When "Counterpoint: the architecture of Daniel Libeskind" opened in Germany last year, its subject was very much the industry's blue-eyed boy. The critics adored him. Libeskind is witty, erudite and also makes for great copy. His buildings, which include Berlin's Jewish Museum and the Imperial War Museum North in Manchester, come neatly packaged with the kind of emotional imagery that makes a journalist's job very easy. At the time, the whole world loved him, too - after all, he was then working on architecture's most prestigious project, the Freedom Tower, designed for the Ground Zero site in New York.
Fast-forward 11 months. With a re-branded exhibition, "Space of Encounter", about to open at the Barbican in London, things don't look quite so pretty. In the past couple of months, it was announced that two of his better-known schemes were in trouble. The Heritage Lottery Fund had refused to grant £15m for the V&A's Spiral, and then Libeskind told the press that he was taking Larry Silverstein, the owner of the Ground Zero site, to court over unpaid fees. The gloss on Libeskind's pristine reputation is slowly being stripped away, and there are a number of reasons why.
First, his attitude to the redevelopment of the World Trade Center. There was something slightly nauseating about the manner in which Libeskind played his emotional cards, talking at length about his feelings on arriving in New York as a Polish immigrant. Indeed, it's a hand he is still happy to play, recently telling the Telegraph's Giles Worsley: "When I saw the collapsing towers I turned to Nina [Libeskind's influential wife] and said, 'I want to go back to Lower Manhattan'." It's a cheap pull on the heartstrings that he has now used too many times.
His studio also became embroiled in an unseemly incident involving a round-robin e-mail sent anonymously by one of its staff. The message asked recipients to write to the New York Times and demand the sacking of its renowned architecture critic Herbert Muschamp. His crime had been to criticise the Freedom Tower. An embarrassed Libeskind moved quickly to distance himself from the note, and an apology followed.
Yet the row focused people's attention on the lack of debate surrounding the winning entry. Last year, a former employee, Markus Miessen, spoke out in Blueprint magazine. He claimed that "Libeskind's World Trade Center complex is concentrating less on its architecture, and more on its media and marketing strategies". He had a point. The campaign to get the final vote was so effective that nobody appeared to worry about the spaces the tower would create, concentrating instead on the fact that it was 1,776ft high (reflecting the date of the American Decla-ration of Independence). Miessen will now only add sagely: "There's a huge gap between the story he tells the media and the way the building is produced." The spin, it seems, has gone too far.
There are more complex reasons for Libeskind's toppling. Over the past year, a new generation has emerged in the architecture world, and they are questioning what has gone before. "We belong to what we could call the second generation of architects operating within a globalised domain of practice," wrote the architectural firm FOA (Foreign Office Architects) for the book accompanying an exhibition at the Institute of Contemporary Arts in London earlier this year. "The previous generation developed what we call a practice of stylistic consistency. But a faster pace of market evolution, increases in the rate of consumption and the level of information and competition between locations have started to render stylistic consistency ineffective." The message is clear. "Signature" architects such as Frank Gehry and Libeskind are old hat.
Further fuel was provided in a recent lecture by Graham Morrison at the Architects' Journal/Bovis Awards for Architecture. "Designers have been falling over themselves to apply the iconic treatment to every conceivable building," he said. "These new designs have names like Spiral, Cocoon, Cloud or Vortex, inspiring a sense of poetic wonder. Often, though, they are just ordinary buildings distorted into unnecessarily complicated shapes." He went on to single out Libeskind, arguing that his recent building for London Metropolitan University was "little more than a cultural placebo" and "a distraction from the university's long-term management issues that might do more harm than good".
The more he builds, the less radical Libeskind seems. This is inevitable, but Miessen sums up the frustration of the new breed of architect when he says: "I don't think his buildings are radical in terms of what they are doing. In the early days, they were radical in terms of the way they looked - the Jewish Museum was quite intriguing in terms of space. But I don't think his buildings do anything for the urban space."
It is difficult to shake the suspicion that we've seen Libeskind operating at his peak, and that the debate has moved on.
"Space of Encounter: the architecture of Daniel Libeskind" is at the Barbican Art Gallery, London EC2 (0845 121 6828) from 16 September to 23 January 2005