I'd say about the same.
The 3D isn't as fundamentally important to the 3DS as the Wiimote was to the Wii, not by a long shot. I'd say without the 3D, it wouldn't have stumbled as much out of the gate due a (probable) lower price point, but on the other hand the 3D effect did turn heads at first like it or not. So I'd say, the same give or take.