I'd say the tomestone event and the achievement certificate system were steps in the right direction only for both to quickly wear thin. They're just not updated often enough and veteran players have likely long since grabbed most of the rewards they wanted from the tomestone events whereas the certificate vendor is rarely updated.

I'd like something closer to World of Warcraft's trading post with new rewards each month. It's not like there's a shortage of potential minions and glamour that could be dangled as rewards cycling in and out over time to deter people missing out.