The “Perfect Sydney art museum” is about to open officially this weekend. That was the consensus view of the Premier, the State Arts Minister and Art Gallery of NSW Director Michael Brand at yesterday’s press preview. “This takes the cake”, confirmed the Arts Minister Ben Franklin. And all were also agreed that this was the most significant building erected in Sydney since the Opera House 50 years ago.

Hang on! Haven’t we only just solved the problems of the acoustics in the SOH Concert Hall? So are we putting the design of the new art gallery on the same pediment, ahead of its fundamental purpose – to show art?

I believe the answer is Yes. Take today’s Sydney Morning Herald coverage of the opening – two architectural reviews (positive) and one story about the 52% women artists present, as if that was a benchmark of anything but political correctness.

And the First Nations art world has pioneered that already. Since the 90s, busy women artists have thrust themselves into the formerly all-male world and recognised that both cultural transfer across generations and community income are almost totally dependent upon their efforts. Way ahead of 52% – with the wonderful Iluwanti Ken from Amata proving just that at the opening in front of her largest representation yet of the eagles that are such a model for the maintenance of strong families.

And, in questioning the architectural/art balance in Sydney Modern (which will probably get an Indigenous name soon), I must admit that there’s been a brave attempt to move the AGNSW’s First Nations art up from the old building’s basement to the new one’s entrance hall.

But herein lies my doubt. For the vast, glass entrance hall challenges your intention to find some art by pointing you directly towards escalators heading down the slopes towards Wooloomooloo, and exciting you to stare down into the cathedral-like heart of the gallery below you. OK – there’s a significant Rusty Peters’ work on a wall to your right. It’s brilliantly chosen – ‘Gamerre – What’s This Museum?’ (2004) in which the Gija artist contrasts the object-laden Western museum with his people’s land-based accumulation of culture.

But is it enough to tempt you to deviate from the obvious path downhill to consider the new Yiribana Gallery beside ‘Gamerre’. It’s certainly worthy of consideration, full of goodies – a major weaving commission from the women of Milingimbi, new engraved works on metal from Yirrkala, a clever series of animated photos from Genevieve Grieve, a pack of Wik & Kugu camp dogs from the Namponan brothers in Aurukun, the glories of rusted metal from the bush ‘bag lady’, Lorraine Connelly-Northey’s hands, a familiar mushroom cloud of Yhonnie Scarce’s glass yams, and some scaled-up Papunya Tula op-art canvases.

But scale is quite a factor. Old (and important) barks from the collection get seriously lost on the walls in this pavilion, even though they’re lower than the generality of Sydney Modern’s vastness. It’s what I call the GOMA problem after the pioneering massiveness of Brisbane’s Modern Art Gallery – requiring art of a comparable size to look half decent. Of course the Japanese architects, SANAA are famous for their glass walls, and these certainly allow gallery-goers a borderless appreciation of Sydney’s glories whenever they’re near the edge – a lot of plants appeal too just beyond the glass. But they require internal pavilions to actually show art, and even these have substantial temporary walls.

Somehow small things survive and shine away from the walls. In Yiribana, a beautifully lit niche with Yolngu cultural objects delighted. In the depths, a tiny ceramic Chinese lily-pond touched the heart. And in an oddly left-over space, two small Asian houses matched the key work in the strongly-curated ‘Dreamhome’ exhibition on Level 3, which was Louise Bourgeois’s small sculpture of hands grasping each other, supporting a precariously balanced house.

For the rest, I’m sure it’ll be the big that will stay in the memory….Lisa Reihana‘s 20 metre screen imagining a pan-Indigenous ‘Crossing of the Ditch’ which seems visible wherever you stand. While the equally wide martial-arts animation by Howie Tsu can only be found by heading into a darkened room marked ‘Outlaw’. Quite as challenging vertically is the American Samara Golden’s vast and limitless version of the ‘Dreamhome’, two and a half glittering storeys extended to infinity by mirrors.

And then you get to the basement, the former oil tank – still stinking of oil – 7 metres high and supporting all the above galleries on 150 pillars. A Guggenheim-challenging white spiral staircase leads into the stygian gloom where stygian artworks by Adrian Villar Rojas are aptly called ‘The End of Imagination’! Many attendants are required to save you from falling into them. But the possibilities down there are appealing.

That Guggenheim reference is a tribute to Premier Perrottet’s heroic claim that “Every great city has a great gallery” – and Sydney Modern matches both claims. It made me cast my mind to London, where I can’t actually conjure any great galleries, but I can think of many great collections.

So will we get the predicted two million visitors and a billion dollars in benefit to the NSW economy from Sydney Modern? Or should we by thinking slightly more maturely about the nexus of culture and money like the Victorians, who’ve quietly accepted the need for a third building at the NGV costing $1.2 billion. I seem to recall that Sydney Modern was not only controversial for appropriating an underwhelming and underused grassy hillside but was also an extravagance at $344 million!

Now we’ve got 50,000 plants (70% more than before) and the prospect of Jonathan Jones’s living Wiradjuri landscape – once they’ve sorted out a dispute with the main landscape architect – ‘bial gwiyungo (the fire is not yet lighted)’.