The first and most major hurdle is to convince people who are used to and still have the option of pretty much the exact same service for free that they should

The first and most major hurdle is to convince people who are used to and still have the option of pretty much the exact same service for free that they should pay anything at all, and that needs to be very low. Letting people choose their price and giving them the little gold badge taps into their emotional response at a very low cost, so stick with it. Beyond that, the Gold features that cost money to implement should require a minimum donation to make them sustainable, and the page that takes the donations should have a 'make this donation recurring' checkbox.