I honestly didn't expect it to be a DS game. But heck... it looks great. Can't wait to get my hands on it.
Several of the demons design are the same from Devil Survivor. For instance the Wendigo.
But I don't think this is SMT4.
Its more likely a 'direct spin-off' much like Shin Megami Tensei If and Shin Megami Tensei NINE were.