This is my plan for Victoria Park:
A great urban forest. Forget Lord Mayor Harbison's great urban park; we have one of those at Rundle Road, or at LeFevre Tce, or pretty much everywhere. What we need is a great urban forest similar to Paris's Bois de Bologne or Hannover's densely forested ring.
It would be simply Adelaide as it was before settlement. Dense-growing gums, she-oaks and other native species would supply an authentic pre-European view of the Adelaide plains. An artificial billabong could be built, perhaps from a diversion of one of the many creeks that run through the eastern parklands.
For human use, to appease those who must have every m^2 'used', and because I would want to enjoy such a forest, I propose paths would be made, not paved, but marked out with stones and sticks. A boardwalk would offer a romantic over-water walk, with numerous spots for sitting and listening. Signs could be errected to show certain species of plant or animal, to inform and entertain those using the forest. A little hut could offer weary hikers with eco-friendly (and perhaps with an emphasis on bush tucker) foodstuffs and hot drinks for those cold winter afternoons.
The key to this urban forest would be non-intervention. The government would weed it occasionally, and ensure that the paths were clear, but otherwise everything would proceed as it would have 200 years ago, before Adelaide was founded. It would be, in 300 years, virgin forest again. Or at least as close as we can get as long as there are feral cats, dogs pooing, and all the other plagues the white man brought with him from Europe.