If the developers of Cainhoy Plantation do indeed want to be sensitive to the surrounding area and respectful of its historic, ecological and cultural assets, they have a long way to go.

The overflow crowd that attended Wednesday’s Charleston Planning Commission meeting made it clear that they need more time, more information and more opportunities to address plans for the 5,000-acre, 19,000-unit project — Charleston’s biggest project ever and one that chairman Frank McCann said could be “our legacy.”

Matt Sloan, who represents the Guggenheim family and corporate interests that own Cainhoy Plantation, said he is happy to meet with groups or individuals to explain the master plan. That’s a good start.

But several people who pleaded for more time to study the complicated issue noted that information was made available only days before the meeting.

Commissioner Valerie Perry was on point when she said charettes are an effective way to get widespread public input and ultimately make for a better outcome. Mr. Sloan, however, stopped short of agreeing to that deliberative planning process for Cainhoy Plantation. And the city’s Tim Keane appeared resistant to the idea. As director of city planning, preservation and sustainability, he should embrace it.

Mr. Sloan also failed to answer a question about the timeline for the project. Wednesday’s presentation to the commission was for information only. But he could return to the commission next month and ask for approval to rezone the property, a step toward beginning development.

Mr. Sloan, who works for the Daniel Island Company apart from his role with the Guggenheims, pointed to some ways developers already have responded to the public. They are working to speed up the widening of Clements Ferry Road, which crosses Cainhoy Plantation; they have helped secure assurances that power lines will be buried; they have moved a site for light industrial use farther from the historic St. Thomas-St. Denis chapel, which is adjacent to the property.

But the public still has not seen the developers’ study of the area’s cultural and historic assets. And environmentalists are still concerned about how the development could adversely affect the property’s longleaf pines, which generally exist in numbers that are dangerously low.

Neighbors are rightly concerned about being driven out of their rural homes and lifestyles by rising real estate values and suburbanization. Mount Pleasant residents are concerned about additional traffic.

Preservationists from the Historic Charleston Foundation and the Preservation Society of Charleston offered their services in reviewing those assets. Mr. Sloan would do well to take them up on that offer.

And local conservationists and people who live in the vicinity of Cainhoy Plantation — who know its environmental and cultural value — would help the planning team shape a better project.

Several members of the commission said they would like to visit the site and see firsthand what is planned. If these knowledgeable people, with experience analyzing and judging projects, feel unready to move forward, it is small wonder that the public feels even more uncertain.

Developers have said it will take decades for Cainhoy Plantation to be fully developed. It is that mammoth.

That scope recommends against rushing through the rezoning process. The design team has been working for a few years, but the public has been brought into the loop only very recently.

Matt Sloan is proud of the highly regarded planning team working on Cainhoy. But planning should also consider projects in context. A roomful of people offered their various talents and insights to help developers better acknowledge Cainhoy Plantation’s context and assets.

Mr. Sloan and his team should recognize that such input, including opinions of local residents expressed at charettes, could help improve the master plan and ensure that this legacy project is the best it can be.