A indicative business case prepared last July put acquiring the central Wellington building and developing it as a national war memorial centre - at a likely cost of $237m - on a shortlist of options to be explored further.
Independent historian Dr Stephen Clarke, former chief executive of the Returned Services Association, said the GWE experience had revealed "obvious pitfalls" around the potential for delays and cost-blowouts for the national museum project.
Clarke said there were issues in the military heritage - chiefly with branches of the armed forces maintaining separate, largely privately held, collections - but these could be resolved by much more cheaply by expanding the mandates of either Te Papa or the Auckland War Memorial Museum.
"Once upon a time I would have been a really strong supporter of the Dominion Museum option, but the cost side of it is extreme and the whole sector is under pressure," he said.
Earlier this week the Herald reported ministers had been aware for years about financial and accountability problems with the GWE - including its centrepiece exhibit being delivered three years late - and taxpayers faced a $12.7m bill when it became time to dismantle it.
Arts, Culture and Heritage Minister Grant Robertson would not be interviewed about current plans for the museum this week, but earlier said his focus was on trying to extend the lease allow the GWE to avoiding closing early.
Documents show a lease extension - understood to be opposed by the current tenant Massey University - would also allow the Government time to prepare a detailed business case to justify buying and redeveloping the Dominion Building as a national military museum.
This GWE pilot had inauspicious beginnings. Documents show despite the date of the World War I commemorations being known for a century, government decisions were only made at a very late stage leading to a haphazard process lacking usual public sector oversight and accountability.
A 2016 letter requesting more funding to ministers from the National Military Heritage Trust - whose members included Jackson and responsible for raising sponsorship and operating the GWE - said they had only been established in November 2014 with the exhibition opening only months later.
"With the decision to commence the temporary exhibition being taken at such a late stage it was considered there was insufficient time to manage the project through government systems," the letter said.
The resulting thrown-together public-private partnership ran into problems early, and it was soon realised hopes to cover operating costs with sponsorship from the private sector were doomed.
"The haste in which the GWE was established meant that it was difficult to accurately predict visitor numbers and resources required to operate," the letter said.
The letter noted the impending end of the lease - expiring at the end of 2018 - meant spending millions more on Sir Peter Jackson's long-delayed Trench Experience "had questionable economic benefit".
The multi-million-dollar Trench Experience - part-funded by Jackson personally - was formally opened in April 2018. Advice to the Government suggests that unless the lease is extended, work to remove it and other elements of the GWE will need to begin within the next few months.
Such a move will trigger "make good" costs to the taxpayer, incurred in returning the building to its original state, of $12.7m.
The business case hints at frustrations from Jackson over the by turns haphazard and drawn-out process, with officials recommending public-private funding options be avoided in future.
"For the GWE, Sir Peter Jackson has made a considerable contribution but that cannot be relied on for the future," the report said.
Last week Jackson told the Weekend Herald while he was supportive of the creation of a permanent war museum, he felt there had been insufficient support from the public sector.
"That requires a commitment from Government, which to date, I don't believe has been forthcoming," he said in a written statement.
