Ok, I figured I'd explain how I have in mind to address both of these factors:
1) Power - we really need to make this a property. I had been thinking of it as something we can't allow to go negative BUT AIAndy illuminated me to the idea that we could have brownout buildings beginning at 0 and then at some point a complete blackout where power doesn't exist. I like this approach. But it's going to take some work to plan and implement.
2) Factories - There's a bigger problem with factories than just factories themselves. The problem is wrapped up in manufactured resources as a whole. And the problem is most exacerbated when you look at corporations and how they work with resources. The volume of manufactured resources is out of balance tremendously and that's across the board. For manufactured resources to have much real value, they need to be a bit tougher to generate, more limited as a whole category. But how do we do that when it's common buildings that make these resources?
In some cases we don't worry about it. Charcoal, for example, is going to be found everywhere we find a fire pit. BUT, maybe not industrial grade charcoal, which we may include as a more limited commodity later on in the tech tree than common charcoal or clay is in the early game.
But for many craft or industrial manufactured resources, we need to make them a bit more special to come by, a little more strategic.
So what my 'coming soon' project is here is zoning regions represented by buildings and production buildings that must qualify by having available zones to fill.
The way it would work is that the city gains zoning slots by gaining population. You then build Zone buildings, such as Manufacturing Zone I, II, III, IV, V, VI and so on, Agricultural Zone I, II, III etc... and so on. These don't accomplish anything but to provide the city with particular zoned TYPE slots, and every so often employ another citizen.
Then the only way you can build one of many categorized building types would be to have an open Zone slot of that type, such as, say, a Jeweler, which would require a Commercial Zone slot. That will limit how many buildings you can build in a city at all, and in particular limit how many manufactured resources can be built. It will invite the specialization of your cities and enhance the strategery of trying to provide for your nation all the needed manufactured resources you can get.