In short, her questions:
1. Is the content unique?
2. Is there competition?
3. Is it possible to put a lid on the content anyway?
4. How many users might you lose?
5. What is your plan behind the firewall to find the community and get it to pay?
It's a soundly argued, sensible series of questions that ought to be part of the discussion as publishers approach the firewall after years of free.