Not much to say beyond the title, really. Beyond missions (which are just rehashes of Clockworks levels anyway), OCH, and Compounds there hasn't been any new PvE content since launch. Veterans are getting antsy; when they get antsy, they leave and tell their friends to avoid this game like the plague.

This doesn't mean new monster families or themes. Heck, I'd be willing to put up with all the problems the return of Sleep would provide if it meant that Three Rings brought back Starlight Cradle. Just make more level layouts to cycle around in the Arcade. This lends both freshness to the arcade and freshness to any new missions, since the level designers will have more existing material to base missions on. It also makes the game more attractive to reviewers who have seen the game in the past.

For all I know, Three Rings is working on this right now. But we can't tell, because Three Rings never says anything about what they're working on until the last minute. The important thing is communication. Even something as simple as "We're working on adding more content; no guarantees" would probably be enough to stop an exodus of veteran players.