Thanks for the feedback!
1. Not sure if it will make it to the next patch, but yes, we will work on connecting walls between more points at some stage.
2. The idea is that it will be unusable so you need to think through where to put it.
3. Yes, this will come. Single player will start getting more focus after the next few patches. :)
4. Yes, naval warfare is part of our roadmap.
5. That is intentional for now. We haven't found a way of preventing this yet without affecting performance too much. Line of sight algorithms can be fairly expensive, especially when there are big battles with lots of units. If you have any ideas let us know!