While I believe that I understand your explanation, I must respectfully disagree. I subscribe to both print and the website versions of WS. Print gives me the articles and wine reviews in print; my digital subscription gives me much of that same material and some additional material, but in a different form, namely digital. I can access that material from my computer or, when I'm away from home, from my phone.
What you've now created is a portal that allows me access to the very same content (or, perhaps less of it) that I've already paid to access. I can access that content via my phone and the specially-designed mobile site. All your app really does is provide me a slightly different way of viewing that same information (I don't really know as no demo is provided).
What content are you providing via the app that is not already available via mobile website (or via the regular website) for which I've already paid for access? What are the "different uses" you mention? Looking up wine ratings via the mobile website is precisely the same as looking up wine ratings via the new app. The only difference is that you've built an app.
I wouldn't mind paying a minimal fee for the app itself (in a range similar to what other apps cost); but the notion that I need to pay a subscription fee to access digital data that I've already paid to access is simply non-sensical.
The other point that I'd ask you to consider is how many loyal subscribers you will alienate and how the virtual chorus of one-star reviews in the AppStore will impact both the reputation of Wine Spectator and the likelihood of a profitable app. Add to that the fact that you will have to share revenue witah Apple, and your business decision makes even less sense.
I implore you to reconsider your decision.
Slight tangent. I just looked up a couple of WS Wine Ratings on my soon to expire online subscription and noticed for the first time that they are asking for a "star" rating on wines based on a 5 star scale at the bottom of the tasting note. Kind of strange that they'd use a 100 point scale and ask for a 1-5 rating from users. Wonder if they're going to incorporate aggregate scores from the herd in their ratings.......
And then there's the way mental_floss treats their customers. Understanding that customers are paying for content, they develop a new IPad app to access their magazine on-line and give it away free to subscribers. Guess where my support and loyalty is going to.
Okay, so in spite of my griping about having to pay twice etc etc, I have to say that I've been using the new iPhone app for well over a month now and it really is very good. I've pulled out the phone at local wine stores to look up ratings and pricing, and it's fast and easy to use. Well worth three bucks a month, especially as I've given up the web and print subscriptions.