The three men's submission said revitalising the CBD would only occur through increased numbers of people visiting the CBD.
"It has nothing to do with architecture and everything to do with activities and amenities which attract people. A good example of this is the jazz festival."
They urged the council to reconsider its priorities and bring forward elements that would actively contribute to amenity, including a purpose-built stadium at the Domain. A stadium would help the council achieve its objectives of a more vibrant city centre and improve local and regional economic development.
"As part of this, we encourage the council to use the term city heart rather than civic heart because that is what the community wants."
A stadium would add substantially to economic development by attracting private investment to the city centre, such as a hotel development. An administration building on its own would not be the catalyst for much needed private sector investment, they said.
"Not everyone likes museums and libraries. A stadium caters to a different demographic. A reasonable proportion of visitors to the stadium would migrate to the CBD after an event.
"The collective attraction of a library, museum and stadium would be a magnet drawing people into the CBD and drive economic activity," the submission said.
They asked the council to re-evaluate the capital cost of a new administration building, saying $64 million was "extremely high".
"Our analysis accords with that of Priority One which indicates the spend should be in the vicinity of $40 million to $45 million."
Their submission also called on the council to lease rather than own the administration building so the council could progress the amenity-based projects that would drive economic benefits for the CBD. They also want a council-owned organisation created to negotiate the development of an administration building and to develop amenities.