1) Path decorations - lampposts, floodlights, bins, benches, fountains, speakers (with custom music would be nice), statues, fossils, dinosaur info boards by paddocks, street signs, poster boards (with custom image support would be nice)
2) Terrain tools - selection of appropriate biome paints (sand, rock, swamp), rocks, plants/bushes, tall grasses, paleo trees that herbivores can feed on
3) High mast lighting in paddocks to light dinos at night
4) Visitor attractions - viewing domes, jeep safari (JW free drive and JP track ride), balloon ride, Cable Gondola ride, boat ride, treetop walking paths and first person mode for all current and future attractions
5) Tour guides that take guests round the park
6) Herbivore feeders - viewing platform feeding trays/guest hand feeders, treetop walk feeding trays
7) Security cameras
8) Raptor paddocks from both JP and JW
9) Sandbox mode with day/night cycle
10) Jurassic Park assets - buildings, main gate, vehicles
11) Larger variety of guest buildings - shops, food stalls, information stations, dino feed. Also the dino balloon I saw in JW and see the guest walking around with it because why not
12) Ability to purchase more land to build on for each island
13) Staff management - manage training, wages, job types, and moods
14) Staff variety - janitors, entertainers, dino experts at each paddock (maybe in the viewing stations)
15) Visitor management - see guest thoughts and needs globally and individually
16) More ways to access the islands - Helipad and ferry port, then jeep ride or monorail to park entrance
17) Aviary and lagoon
18) Paddock cleaning - dinos do a doo doo, rangers go clean it up
19) Separate restricted staff areas and visitor areas - build all your important staff buildings (power, ACU, expedition centre, fossil and research) away from the main park and have a path locked off via a staff gate
20) Underground power cables
21) maintenance sheds/bunkers for running backup power systems/power relays between different power stations
I'll probably edit this as I think of more stuff
-- side note: ability to pre-load the game for pre-orders