I also had trouble deciding what should be the default option for looking cross corners for my own system. I’ve made both options available for users, as I’ve seen both methods used in different games. Allowing for crossing corners is currently the default option, but it could really have been either way.
Edit: I think it might even be useful to make both options available in the same game. That way you could allow for looking through corners of buildings, but not in between two boxes placed next to each other.
Here’s an image of how it looks in my system with walls blocking (grey) and not blocking (blue) vision past corners.
