I think it'd be a waste of resources to have it as a fully fledged feature. Computer resource would be far better used elsewhere i.e. keeping huge parks running lag-free. I would rather the emphasis be on the parks, rather than the water. As long as the water looks great, the dynamics of it and the physics of every digital drop is un-important. I can see a great way of using physics based water as a tool though.
How about a dynamic water generator tool? It could work as way of creating rapids, waterfalls, or fast flowing water. The way it would work is this,
1 You sculpt the land to make rivers, or lakes or what would be waterfalls.
2 You then click on the bottom body of water to fill it.
3 Click to fill the upper body of water.
4 The water then flows using the water physics until it reaches the bottom body of water.
5 At this point, it is saved as a looping animation and the physics engine is switched off as it isn't needed.
This way, you could have many water features in your park as they're all just animations and not a complex dynamically calculated set of fluid objects.
Or an even simpler system could be this,
1 You make the upper and lower bodies of water.
2 You click and drag between them
3 The tool generates a moving water animation between the two, joining the edges close to the terrain.
I just hope there is something so we can build waterfalls.
