What was required to create a vibrant waterfront was a long-term directive pushing activity to the harbour edge - something Auckland has only recently started to take seriously, he said.
"Grand opportunities come and go and history has shown a poor priority given to the city's frontage," Mr Mercer said. "Auckland must continue to find the courage to let good architecture and urban design take the stage."
A grand waterfront vision would guide bold decisions independent of the city's three-yearly political cycle - "we can't resist the allure of the Waitemata".
Historically, there have been many opportunities on the waterfront.
The Aotea Centre was once planned for the waterfront, a chance for something similar to Bilbao's famous Guggenheim Museum.
But Auckland built the performing arts centre near the Town Hall instead - without a final design and at cheaper cost. The project became a construction nightmare, its 30-month timetable running nearly two years late. The budget nearly doubled.
A casino and, more recently, a Rugby World Cup stadium were debated for the waterfront before being scrapped. Meanwhile, a tunnel across the harbour could have created the opportunity to have subway stations along Quay St and further down the waterfront.
There has been frequent talk - without action - of putting a statement building on the waterfront, including a suggestion for a Sir Edmund Hillary convention centre.
Going further back, the waterfront once had several attractions, some of which are being proposed again, decades later.
A waterfront park at the start of the 20th century, Luna Park, featured a roller-coaster looking over the city. A sea promenade ran the entire width of the waterfront, and an extensive ferry service connected most of the outlying coastal suburbs.
Until mid-century, trams ran down Queen St and along Customs St, linking the city to the waterfront.
Nearby, a collection of 19th-century merchant buildings, designed by the best colonial architects, were crisscrossed by picturesque alleyways. This area, which would have rivalled Sydney's historical waterfront precinct, the Rocks, was demolished for a carpark.
A city beach was once possible near Princes Wharf until developments, and wharf markets in historical sheds until their dismantling. In the Wynyard Quarter, an enlarged Victoria Park was rejected, though a green space is now planned for the point, with the possibility of a cricket ground nearby.
Waterfront Auckland chairman Bob Harvey said Auckland had turned a corner since the Super City was set up.
"A major starting point has been, for the first time, the creation of one integrated action plan that Auckland's waterfront has been calling out for for many years," Mr Harvey said.
The Waterfront Plan looked ahead 30 years to try to sustain the momentum for change. It was built on the work of former councils and contained the voices of many stakeholders and the public.
"While some may have the impression there's not enough direction or leadership of waterfront development, that an incremental decade by decade approach is being taken to the waterfront, the opposite it true," Mr Harvey said.
There was more planning than ever before, and more Aucklanders were being included in the process.
"The creation of Waterfront Auckland itself is evidence of the importance which Auckland Council places on this aspect of the city's development," he said.
Planning lecturer Joel Cayford said there were several lessons to be learned from past developments.
"Whenever you do things piecemeal, you make mistakes."
It was essential that Waterfront Auckland planned ahead for the entire waterfront, he said. Even the otherwise robust Waterfront Plan could be criticised for not looking at the whole picture.
"The mistake that was made was to exclude the port planning from the waterfront planning. It's like removing an essential ingredient from a recipe - like removing flour from a cake."
The more recent waterfront developments constituted a spectrum of success from Princes Wharf to Wynyard Quarter.
Princes Wharf overemphasised its hotel and cruise ship terminal, Dr Cayford said. "The public realm is a kind of embarrassing strip around the edge - how sad is Princes Wharf?"
It did not have any public toilets, helping to turn people away. "It's a really simple thing, but if you're older and need to go to the loo every hour, you won't go there. And if you've got a baby, you won't go there. You can unwittingly design a public space to alienate large demographics."
Next step up the line towards a successful public space was the Viaduct Harbour, Dr Cayford said, and it showed how private interests could encroach on attractive places.
"All it really consists of [now] is quite expensive restaurants, for the 20 to 30-year-olds, and lots of places to drink lager outside. It's a bit of a lager alley."
The area had been envisioned to be entwined with commercial fishing activities, offering an authentic vibrancy of "fishing boats and all the things that create the noise and energy".
"The public could stop and watch the boats unloading, though it would smell a bit like fish guts."
But the activities came to be considered "too unsavoury", he said.
"What happened was the residents got grumpy because fishermen might swear from time to time, or leave or come back at 5am. People weren't able to use their balconies, so they extended their private control over the public realm and forced the council to bring in bylaws that fishing boats couldn't use the wharves anymore.
"That has to be guarded against, very, very strongly. Or the public realm becomes a footpath to go from A to B."
Though it could yet suffer the same fate, Wynyard Quarter had so far been successful, with good planning processes that included public consultation and zoning.
"The planning is much, much more thoughtful and provides for a range of experiences, from cheap to more expensive, lots of open spaces, the playground, seating areas for people who are younger and older, and there's a reasonably good provision of public toilets," Dr Cayford said.
"It involved public input and private sector input. They all had an input into the plan, and shaped what they built down there."
He noted that no similar process had yet been followed for Queens Wharf.
For Auckland, there had been a process of expanding the concept of public spaces from just roads and negligible footpaths to areas with all the necessary provisions. Without them, open spaces could end up like Aotea Square, "which is an afterthought, really", he said.
"The responsible way to tackle the waterfront from now on is: We really stuffed up in Princes Wharf. We partially stuffed up in the Viaduct. We did some good in Wynyard Quarter. We need to apply this to Quay St and Queens Wharf.
"So let's get on with it."
Lost opportunities
Harbour Bridge
Auckland's major project in the mid-20th century lasted just 10 years before reaching its capacity. The Harbour Bridge, completed in 1959, had only half the number of lanes it would soon need. Clip-on lanes doubled the capacity, but today it is again insufficient, demanding a second harbour crossing.
Britomart's dead-end rail
The rail tunnel to Britomart Transport Centre was completed in 2000, creating a dead-end service with only two ways out of five platforms. But at the time it was built, the station's limited capacity was criticised as too much for Auckland. Mayor Len Brown's desired inner-city rail loop would open the station on both ends.
Quay Park
Quay Park was one of the city's big developments a couple of decades ago, but has experienced general disappointment. The large area east of Britomart, including the former site for an Oriental market, was turned into residences and offices. Leaky apartment units in the old railway station building sold for a record-low $12,800 in 2008.
Waterfront stadium
When New Zealand won hosting rights for the Rugby World Cup last decade, there was talk of a bold waterfront national stadium. But the hurried, uncosted and unplanned idea crumbled. The alternative, an expanded Eden Park, still ended up costing $256 million.
Princes Wharf
Princes Wharf was turned into public land in 1998, and the hotel site, which links to the Viaduct Harbour, is home to restaurants and bars. But despite its prime location on a wharf, the area is notoriously deadened the further you go out toward the harbour.
The campaign
This week, we examine the key issues in a campaign to break open Auckland's waterfront. This means:
1) Opening up what's already there for everyone's use - particularly Queens Wharf, which is still far from reaching its potential.
2) Looking ahead to more wharves being opened, notably Captain Cook Wharf; and
3) Planning the entire waterfront - importantly, including ports land - as urban space, whether or not the working port is retained or developed.
Monday: What readers want on the waterfront
Today: Auckland Architecture Association sketches the all-time good ideas
Tomorrow: Tourism on the waterfront
Thursday: The working port and its vision for Auckland
Friday: Where our city leaders stand.
Tell us what you want on your waterfront
(email newsdesk@nzherald.co.nz):
A convention centre?
A performing arts centre?
More ferries around the Gulf?
A waterfront stadium?
Night markets?
Waterfront apartments?
Performance spaces?
Public art?
Te Papa North?
A world-leading university?
"Our grandparents gave us a four-lane harbour bridge when we needed eight, our parents the Aotea Centre when we wanted an Opera House... what will our children thank us for?" - Heart of the City.
