Rage isn't even out, but that's not about to stop id Software's Tim Willits from being hopeful that the game will be successful enough to warrant a sequel, and speaking more generally about the subject to GamesIndustry.biz.
"You need to make a franchise. Especially for us. We're doing everything we can to turn Rage into a franchise, please let it sell so we can make another one."
"We definitely, from the get go, planned to make this a much bigger franchise, a much richer world, that allows us to have different games, and we can make more mobile games, heck, we could make a social game with Rage if we wanted to. And hopefully we can make a Rage 2. Hopefully."
While I don't think sequels are inherently bad -- in fact, the opposite is true quite frequently in this industry -- studios need to step up their endings. If you do have long-term franchise plans, don't make that blatantly obvious with a cliff hanger, please.
id Software: "You need to make a franchise" [GamesIndustry.biz]