IS THE NEW ARCHITECTURAL century still stuck in the end of the last one? Yes, but not for long. Asked to take stock of their discipline, architects largely agree that one era is winding down and another is beginning.

Starchitecture—which has given the world more than 15 years of autographed, iconic and would-be iconic buildings—is ending, says Matthias Sauerbruch. The German architect started his career at Rem Koolhaas’s Office for Metropolitan Architecture (OMA), and went on to found Sauerbruch Hutton in 1989 with his wife, British architect Louisa Hutton.

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If the standout museum is a symbol of a previous era, the luxury residential high-rise, taking over skylines from New York to Singapore, can seem like a symbol of the new one. Mr. Gadanho has low expectations for the actual architecture these projects are generating. The history of the discipline is marked by individual wealthy clients prodding architects to test their artistic boundaries, but “the abstract patrons” of these high-rises, built for dozens of anonymous buyers, is necessarily “conservative,” he says.

Dutch architect Ben van Berkel, co-founder and principal architect of UNStudio, disagrees. With offices in Amsterdam, Hong Kong and Shanghai, UNStudio is currently building two of the more compelling luxury high-rises around: London’s Canaletto and Singapore’s Scotts Tower, both 31 stories and set for completion by 2016. For Mr. van Berkel, the challenge is to turn a cluster of wealthy buyers into neighbors. “Luxury is lonely,” he says. The streamlined Canaletto will include community-fostering amenities, like a residents’ cinema and gym.

Sustainability has been a significant inspiration to a generation of architects, but now many worry it’s little more than a buzzword. The goals of the movement still excite MoMA’s Mr. Gadanho, citing a recent installation at the museum’s PS1 of a tower made out of biodegradable bricks, devised by The Living, a New York studio. But Mr. van Berkel speaks for many in the field when he says that the word itself “is kind of hollow now.” In the future, sustainable principles may be filling up building codes rather than firing architects’ imaginations.