At this point, Cryptic Studios has a stable of games based off of existing IPs, most notably Star Trek Online, Neverwinter, and the upcoming game based on Magic: the Gathering. A new interview on GamesIndustry.biz with CEO Stephen D’Angelo discusses working with the IP and making a successful game out of it, noting that first and foremost it’s a matter of finding the core element of the IP that makes it interesting and designing the game around that.
D’Angelo explains that the studio’s core goal is to expand beyond the existing audience for the IP by exploring new directions, rather than trying to solely cover the same material as the original; he notes that the expansion into Magic: the Gathering made sense due to a strong working relationship with Wizards of the Coast and the desire to not simply make an online version of the same card game. The studio wants to explore the world from another angle, just like Neverwinter doesn’t simply plug the stats of the tabletop game into digital form. If you’re interested in the mechanisms of making an IP-based MMO work, the full interview is worth a read.