I hope that the policies will be able to model some concepts of urban planning that have cropped up in recent years and were not as popular in the time Simcity has its roots. For example, Las Vegas gives huge property tax cuts to LEED-certified "green" buildings, which is great for many aspects of city life (less pollution, power usage, water usage, water pollution) but costs the city a lot in revenue. Core to this kind of policy is that the city doesn't need to do anything, though; it simply creates incentives for the simulator to give a more beneficial result.
What I would love, and this may well be a silly dream, is if I could incentive the use of photovoltaic panels on homes (as many cities do) and thus reduce the load on the city grid...but the results would be stronger for houses that are longer on their east-west axis, compared to north-south or square houses.
I've done some work in sustainable stormwater infrastructure as well, though that really only makes sense if watersheds are modeled (not too difficult, based on elevation) and if you can choose, for example, between a combined system for sewage and stormwater or not--the former being common in older areas of cities in real life, and being cheaper in the short term.
We can't really say much about these before we're further in the development though. The basic idea is that you can set the policies globally to the entire map or for each district. All of them have some pros and cons and there will be different types with more or less effect in gameplay. However if you don't want to set any policies you don't have to. This is one of the additional features that suits some play styles but is not necessary for success in the game (like districts).
