Medium could actually make it pretty easy for us to earn referrals, if they chose to do this:
1. If someone hits the paywall while trying to read one of your stories, present them with your referral page.
2. At the bottom of each of your stories, automatically add a "become a member and support XYZ" button (similar to how they now show the email subscription).
Right now, as you rightly point out, it's hard to convert anyone. People are most likely to convert just after reading a story of yours. That's when they need to see the "become a member button". And yeah, as you point out, an almost blank landing page doesn't help in that.