The four spaces where I have put red dots used to be part of the islands (compare to the representative image), and I've pushed those out.
2 more data points to support your hypothesis.
Now that you mention it, in the two games of Atoll I've played the space you marked did seem overly important. I just hadn't played enough to determine if difference was real or just something that happened to pop up during a couple games with inexperienced players. I wouldn't call those space "overpowering" or anything, just slightly more powerful than average.
But how bad is that?