I know this thread is over 1 year old, but feel that I need to add some things here. Yeah, I know real-like waterflow is hard to make, but not as hard as you think. Look at Minecraft - true, water is blocky there, but it flows and it flows quite good. It's all matter of figuring out good block size so it will look like fluid even on high zoom. Also you forget some things that applies to open source/indie games, but not to big commercial ones. That's right - money needed. You don't have to pay testers - fans of game would download latest build and report any bugs their find. Frankly that's how it work for Simutrans. It's using isometric graphic engine which is quite similar to Simcity 2000's.
Simcity 2k:
Simutrans:
And because it's a transportation game with publicly available code we don't have to code transport system = less money used for research and development. All we need to code is zoning, taxes, advisers and placing buildings. Simutrans also has great content tools. I'm currently working for futuristic game pak for it. Graphics and sounds we can either take from Simutrans or ask some artists. I know at least 2 guys and one girl who would do this for free. Games like that doesn't need marketing either. All they need is posts on boards like this one saying basically "Hey, this game exist, you can download builds from here and if you come upon bug please report. Thanks".
So your $14 milion went down to... Less than $1k (basically hosting costs and paying some programmers, but most contributions would be free because of open source nature)