As I mentioned, it's not actually down that much from February, which Nintendo put at 130k between retail and digital. I'm not sure what the true breakdown between both were, and I can't seem to find any indication if it was revealed in the last NPD thread, but the game has legs, surprisingly enough.
Taken on their own, they're definitely not great numbers, but it's not doing terrible for itself. It does lead more credence to the idea that Nintendo has created a very toxic culture on the Wii U, where it can't even engage the diehards enough to buy sure things like SM3DW in great numbers, and that's something that they desperately need to fix really quick here. There seems to be a lot of positive hype for Mario Kart 8, both from guys like us and from the press, and the Smash Direct was well received, but they need to be doing that stuff for everything going forward, and not just announcing something out of the blue and going "Ehh? Ehhhhh?" while it's looking back-and-forth between the game and a confused group of customers.