
For the bonuses, I still think +4 for Central. Also, I think +3 was good for Upper Right. Even though it's 7 territories, it only has 2 borders, both of which are to just one other region. And despite the number of borders, Upper Central should be +3.
Try to imagine a team game with the bonuses you have where one of the teams gets the 3 top right regions. Assuming they also own the top Lower Right territory, that's +15 for only 19 territories and only 2 defense points! Yikes! I'm okay with making Upper Central slightly undervalued on its own, only if you own one of the bordering regions. Besides, if you own Upper Right, what else are you going to take?

The impassable borders are pretty good. The Upper Central one is great, but perhaps in Central Left make it slightly more clear that the territory with the word "Left" in it connects with the one above it.