Your idea kind of reminds me of those world building management games, but many are just a big look at the world where you place buildings, but don't to walk around. It sounds like in your case you will be able to walk around, is that correct?
Also, perhaps letting the put things just "anywhere" may be too loose, as you said possibly making everything pointless.
Perhaps you can build ideas that would force the player to be a bit more "strategic" with the placement.
So, I guess an example could be like with your power plant, it could be "required" or simply be more "effective" if placed near water, for power cooling purposes.
Or for healing stations, more effective when placed near it supplies source, herbs=forest. Then you could limit the amount of places that can be placed near those. So, you could have it where there is only so much forest area, but 2 types of buildings utilize it, therefore players have to decide what they want more of and how to get the most output from their placement.
That could bring a more strategic game play element to your world building, maybe.....
I don't play alot of those kinds of games, so this is just a thought.