With what exclusive software? Xenoblade? Are people already forgetting how the OG 3DS sold when it had no games? Shiny hardware alone doesn't make sales. They need a compelling title to go along with the release to get people to dump their current 3DS for a new one. As of right now, I don't see it selling gangbusters from the jump. Maybe if they made a Youkai Watch 3 or something.
The new 3DS will replace the actual 3DS model. It doesn't need exclusive games.