According to German GameFront, Square Enix has registered several new trademarks with the United States Patent Office, including "Dragon Quest Heroes", "Dragon Quest Swords", "Rocket Slime", and "The Masked Queen and the Tower of Mirrors". A Dragon Quest theme is quite apparent; the games themselves are not. Perhaps "Rocket Slime" is really Slime Morimori in disguise, and "The Masked Queen and the Towers of Mirrors" an English subtitle for Dragon Quest Yangus. Then again, perhaps not.
For reference sake, morimori means 'swelling' or 'full of gusto'. So perhaps rocket is the English translation to be used. It's all good, though it might also mean older Dragon Quest games being brought out.