For a certain kind of architect, the inner harbor of Oslo must be paradise. The pearlescent light, evincing brightly or broodily up from the water, is heavenly; the bustling array of working boats, charismatic ferries, and tall ships offers a stimulating vocabulary of masts and lines and funnels and bulkheads to all modernists who ever thrilled to anything mechanical and maritime.

One such architect is Renzo Piano, FAIA, whose handsome Astrup Fearnley Museum of Modern Art now anchors the shiny (and visibly developer-driven) Tjuvholmen neighborhood along the western edge of that harbor. The former shipyard area may become home to other collections, such as the Munch Museum and the Viking Ship museum, as part of the ongoing Fjord City urban renewal scheme that saw Snøhetta's notable Opera House debut in 2008.

Piano's museum complex unites three freestanding pavilions (some 45,000 square feet of galleries in two exhibition structures and a small office block) across a narrow water channel, under what you could call, thanks to some strenuously bridging strips, one big roof. That roof, compound and glassy in the typical Piano manner, curves along multiple axes like a segment of a sphere, or—the assertion is more convincing in the Piano sketch adorning the museum's tote bag—an Utzonesque sail. Inside, those tilting curves spanning several narrowly triangular galleries produce a sometimes restless setting for art. But much of the art in this private collection (masculinist works from Jeff Koons to Damien Hirst, Matthew Barney to Anselm Kiefer) neither requires, nor always withstands, the long contemplation that more delicately composed rooms would prompt.

The building is attractively clad in deck-like silvery aspen boards, distantly recalling the wood siding on Piano's 1986 Menil Collection in Houston. There are some big white freestanding cable-stayed steel columns that support, along with a suspiciously small tributary area of roof structure, a mast-like gesture towards the nearby marina. There's a looseness to much of the detailing, as in the uncertain encounter of glazing and structural systems at the junction of roof and wall, that suggests, at best, a pro confident enough in the big picture not to sweat the small stuff. That casual detailing, along with the outdoor circulation between pavilions and an unpretentious approach to ceremonial and transitional spaces, bespeaks an egalitarian informality and intimacy between the galleries and that spectacular harbor cityscape—but also a certain lack of coherence at the finest grain of resolution.

One of the myriad cruelties of architectural practice is that designers at the profession's pinnacle have spent lifetimes in pursuit of work for which, when it's finally reliably abundant, they have not enough time. Or they find themselves a name atop an office from which their own hand recedes. On the other side of that tale are impressively lively local architecture scenes like Norway's—with feisty institutions like DogA, the Norwegian Center for Design and Architecture (look for its rousing post-Sustainability Triennial in 2013) as well as smart young firms like Helen&Hard and FantasticNorway—all developing a discourse as brilliant and brooding as that northern light. Once upon a time, the Pompidou Center in Paris opted not for the blue-chip starchitects of its era, but found through a juried competition young designers, Piano and Rogers, whose project, because it was audacious but meticulous, became a masterpiece. What might the Astrup Fearnley museum have discovered, surrounded and supported by that lively local scene, had it taken such a risk?