Weirdly a lot of this was already "available". Albeit marked as being experimental. For example, I've been using the members feature and email newsletter feature for a few months, and I have an accent colour selected already.
The thing I'd like them to focus on next would be for a better mobile/tablet interface. I don't think we'll ever see a native app from them, seeing as they are a web company. But I'd settle for a website that's at least usable on an iPad.
I use Ghost to host this blog and my newsletter, so it's good to see someone else enjoying it. Jeff's experience seems to match up with mine, it's a great service, but it can still be improved in a few ways like he mentions.
One of the big reasons why I think I'll stick with Ghost is the member/newsletter support. Without that integration, I could imagine switching back to WordPress in the future. But for now, everything seems pretty good here.