Deeply dissatisfied with Robert A.M. Stern's design for a Revolutionary War museum near Independence Hall, the Philadelphia Art Commission has taken the unusual - and welcome - step of asking the prominent New York architect to go back to the drawing board.

Although the commission did not reject the $150 million project outright, it sent a clear message to the organizers Feb. 5, saying that the faux-colonial home planned for the Museum of the American Revolution Center did not measure up to authentic colonial-era buildings nearby. The commission asked the architects to remove a Disneyesque cupola, add eye-level windows on Chestnut Street, and reconsider the building's composition.

Few Philadelphians may be aware that a privately run nonprofit organization had been planning a large new museum at Third and Chestnut, now the home of a fortresslike, redbrick visitor center built for the Bicentennial. The museum unveiled its design in the summer of 2012, after philanthropist H.F. "Gerry" Lenfest announced he would donate $40 million to the effort. (Lenfest is an owner of Interstate General Media, which publishes The Inquirer.)

Nothing much happened after that - at least in public. Buoyed by Lenfest's pledge, the museum board instructed the firm of Robert A.M. Stern Architects to prepare detailed documents necessary to construct the design. The firm is now more than halfway done, and the museum has received pledges of $30 million from the state and $10 million from the Oneida Indian Nation.

Without the Art Commission's bold action last week, the project probably would have broken ground without much serious design review. That is shocking, given that it occupies a vibrant Old City intersection and is situated directly across the street from Samuel Blodgett's 18th-century First Bank of the United States, a dignified, classical temple frosted in thick white marble.

The museum had mistakenly assumed that it did not have to submit its plans to the Art Commission because the site was originally owned by the National Park Service, which is not subject to city zoning and planning controls. But that situation changed in 2009 when the Park Service agreed to give the museum the site in exchange for 78 acres of private land adjacent to Valley Forge National Historical Park.

In the last decade, Stern's firm has become ubiquitous in Philadelphia, churning out buildings in a wide variety of styles, from the handsomely modern Comcast tower to historical pastiches such as the University of Pennsylvania's McNeil Center for Early American Studies. While the firm can produce buildings that are sensitive to their urban context, such as Drexel's new LeBow Hall, its historicist designs tend to look cheap and fake.

The Revolutionary War museum was conceived as an abstracted, flattened version of Independence Hall, complete with side wings and the cliched cupola. But its massiveness and modern materials - including a panelized veneer of thin bricks - would make it more cartoon than homage.

"This building really has a big-box-store mentality with a little bit of ornament attached," said David B. Brownlee, a Penn art historian and vice chair of the Design Advocacy Group. The volunteer group severely criticized the design in 2012 (as did this critic).

One of the first questions Art Commission members asked when they saw the design last week was why the museum had not heeded the group's design suggestions.

Although it sent the architects away with a list of requested changes, it is unclear how much the design can be improved. For instance, the Chestnut Street facade is blank on the lower portion because of a floor-level change on the inside. Ironically, one of that things that makes the Bicentennial visitor center such an awful building is its blank, redbrick expanse. Stern's design would enshrine the condition for another generation.

The commission faced a similar predicament in 2009 when the design for the new Family Court was presented as a done deal. It, too, was sent back for revisions, but ultimately approved after superficial changes. In this case, the Art Commission has formed a special committee to work with the museum. It also agreed to let the visitor center be demolished so the site will be ready for construction to start this summer.

Lenfest, for one, said he was not bothered by the commission's decision. "We welcome their input. Anything they can do to improve the building is good," he said, before adding: "I've never liked the cupola. If that were removed, it wouldn't bother me."

At the same time, he defended the building's historical style. "I think it blends with the historic district. We didn't want to create something that would clash."

Museum vice president ZeeAnn Mason said the architects were now working on a response. "We do think there are things we can do and are eager to explore solutions," she said.

Art Commission chairman Sean Buffington acknowledged that improving the design at this late moment will be a challenge. "It's not the role of the commission to micromanage the design," he said. "All we can do is ensure that the building interacts in a positive way with the public space."