Excellent overview and an exciting direction ahead! I’ve played around with SteemPress since the beginning, but I’ve been very lax at updating and building my own sites recently. This kind of stuff is inspiration to get back to it!
I love the email marketing aspect you’re bringing to it through the guest account signups. That could be a huge success in recruiting and retaining.
Users who create a "guest account" through email to engage with blogs will be put on a pathway to earn a free Steem account through engaging with content. A level-up bar will show much their comments have earned them from upvotes, and that reaching 5 Steem Power will allow them to claim a free Steem account. They'll also find a recommended set of activities to help them receive votes in order to progress. They are also encouraged to connect an existing or buy a new Steem account to immediately access anything their guest comments have earned them