The improved lawns around the sanctuary will make good PNE space. That combine with some actually properly built solid surfaces (Festival and Miller Plazas, and The Parade) vastly increases the space available to the PNE.
This year I've been to a few events at Holland Park in Surrey, and it's been a great host. The park is a nice, open green-space most of the year, but when needed turns into amazing event space. The lawn holds up amazingly well to foot traffic and the permanent infrastructure is perfectly incorporated into the event.
The same will be true for the improved land around the Sanctuary. Most of the year it will be great lawns, perfect for sitting around, enjoying a picnic, or playing frizbee (like the land around Trout Lake). And during the PNE, when typically grass gets pretty brown, it will make great event space. The plans call for proper plumbing and electrical hookups incorporated into the lawn space so setting up for events will be fast.
As well, the paved areas are being improved. The main strip through the park will be wider (and permanent) and host stalls during the PNE, and potentially anytime. The proposed Festival plaza sounds fantastic and will be miraculous during the Fair with how it integrates with the livestock building. Playland will be larger, and the concessions will be double sided, so Playland can sell food to people inside AND outside Playland (like to spectators at the Amphitheater).
To me, it sounds like the Fair will be better than ever!
Outside the PNE time, the area can host cultural events or festivals, much like Holland Park. There are enough groups out there that want to do things, but space is in short supply and expensive. Currently you have to close down streets and hold block parties, but that comes with decreased parking and accessibility. NEFC is soon to become condos, and that event space will be gone. Proper community event space is severely lacking in Vancouver, and this space will be great for the PNE, but even better for the community at large.
With the improved public square, amphitheater, Coliseum, flat building, racetrack/casino, and larger grounds, Hastings Park can see events all summer long. Open with a spring festival, and almost every week could see something happening at the park, be it a concert, festival, cultural event, or some kind of party or trade show. The Coliseum, Playland, and Racetrack can see improved business by people attending events, and events could see increased attendance via people going to the Coliseum, Playland and the Racetrack.
It will be possible to spend an entire day at Hastings Park (much like you can spend an entire day at Stanley Park). You can walk around the Sanctuary and down to Burrard Inlet, attend cultural events, see a musical/stage performance, see horse racing, ride some rides, all in one day.
I would really like to see the parking structure built. It would increase capacity and save space. The park is a long way away for a lot of people, and mustering up a family of small children can be challenging on Transit, so parking is important. A parking structure makes people feel there will be parking, reducing risk, making it easier to decide to go. The parking is in a great position for the racetrack, Coliseum, and PNE. And the new NW entrance to Playland nicely connects it to the Coliseum, Racetrack and Parking.
The only real shame to this whole plan is the 20 year time frame. This is something that should be fast tracked as the benefits would be greatly felt by the people of the city AND the metro. I know the money is a sticking point, but Hastings park is regionally enjoyed, and as such they should seek provincial and federal funding. The upgrades to the 100 year old PNE alone should qualify it for some major federal grants.