Roger Hall's vision was bold - as bold as the soldier-farmers back from the First World War, who looked at a few bush-covered hillsides and saw prosperity.

As he describes in the author's note to his latest stage work, he "had the idea to write an epic play about farming".

Hall traces the history of a Hawkes Bay farming clan, the McDonalds, from First World War vet John and his teacher wife Beth, through their sons Richard and Hugh, to Hugh's son, Peter.

For 80 years we watch the comings and goings of wives, children and neighbours, viewing the issues of the times through their lives.

We are given a grand sweep of history, but where this play fails - and fails badly - is that it does nothing more than trace an outline, leaving the characters as historical mannequins, representatives of a time and place without drama or complexity.

A Way of Life is epic in breadth but has the depth of a sitcom.

Sadly, Hall has been conquered by the scale of his vision. The need to set up each era and generation leaves no room for a story to evolve or themes to be explored.

In each generation a series of introductions is made, but the characters move on before there's any chance of a full conversation.

For the first three-quarters of the play, the history defeats the narrative.

This might be fascinating if it weren't for the fact that the history is one-dimensional. It's History 101.

Hall uses familiarity to good effect in his comedies - we laugh at the folk we recognise from our everyday lives - but here it is tedious cliche: the jolly swagman, the rugged pioneer, the Wellington-hating farmer.

During the odd stylised bush burn-off sequence, I was reminded of a pioneer display I once saw in Portland at the end of the Oregon Trail.

Throughout the first half, this was like a performance you might see at a World Expo or other attraction introducing tourists to New Zealand history.

Instances of Kiwiana spring up - the Auckland Weekly News, Dad and Dave on radio, 6 o'clock closing ... even a bizarre Chicks-like song.

Too often these are tokens - mentioned for their nostalgia value alone - rather than servants of the narrative. It's as if Hall is guiding us around a series of display cases in Te Papa.

For a homegrown audience, this is inadequate. Perhaps it is a problem of different generational perspectives.

For Hall and many of his generation, New Zealand's history was much ignored. But in generations younger than Hall's, there is a wider knowledge of our stories, and parts of the play that might be revelatory to his generation appear hackneyed to those younger.

With such a grand sweep, grand themes are there for the taking - the connection with the land, the tension between the generations, the isolation of country and farm ...

Each appear as cows before a passing train and are gone as quickly.

Although the loudest of Mark Wright's cliche cameos - as an American tourist watching cricket, shouting "is 26 slash four bad?" - comes near the end, the play does improve as it enters the 80s.

Like the third generation son on the farm, Hall doesn't have to work as hard in this decade to set the scene, and the story is the better for it.

It also benefits from the appearance of Robyn Malcolm as the embattled modern farm wife, ably supported by Malcolm Murray and Sean Allen.

Here at last is some palpable emotion, some tense acting and writing that makes you hold your breath.

Come the closing auction and the bravely downbeat ending, we can finally feel empathy for the McDonalds and their struggles.

But to borrow American slang from one Second World War character, by that stage this way of life had already "bought the farm".