I'm personally guessing Puzzle and Dragons won't have too much issue reaching 1 million, in sales considering how consistent it's been at or near the top of pre-order charts for a while. I wonder if it sees significant success if they'll be an influx on popular smartphone games on the 3DS or handhelds in general.
I mean if you really think about it there's no reason there shouldn't be. Angry birds despite being ridiculously cheap on smartphones is still the most popular third party game on the 3ds outside of Japan. Considering how much higher the revenue on the 3DS is in comparison to a sale on smart phones there's no way rovio didn't laugh all the way to the bank on that venture.
Chances theres significant overlap between smartphones and handheld devices especially in Japan. Smart phone games and handheld games really aren't all that dissimilar. I think there's a lot of profit to be made from selling premium versions of their smartphone games on handhelds, a market trained to spend a lot more up front on a single game.