We've recently seen Nintendo slowly creep towards cross-buy by allowing the 3DS/Wii U Squids Odyssey to offer a cross-buy opportunity.
Obviously, Nintendo is doing better with the Wii U -- but they still have their work cut out for them in building their active install base. One of their warmest market of potential buyers for the Wii U would have to be 3DS users that don't own a Wii U.
I think if Nintendo allowed 3DS buyers of SSB to upgrade to the Wii U version at a reduced price, I think you might see a faster migration of 3DS users towards the Wii U. Likewise, the same applies for Wii U owners who don't own a 3DS (though from what I understand, that's a small number of people -- but I believe its larger than what most might think).
I figure if you allowed 3DS users to upgrade to the Wii U version for $30 and the Wii U users to purchase the 3DS version for $10 -- that's roughly $70 USD for a pretty compelling cross buy package that'll prompt a lot of users to buy new systems because such a great offer is available to them.
Granted, it may generate less revenue than if users bought both versions for full retail -- but if it drives up the userbase for the Wii U while adding some extra momentum for 3DS, it may be an endeavor that pays off in the long run with more software sales in the long run because of the higher install base for both systems. Amiibo might also help recover some of the lost revenue from cross-buy. For many hardcore NIntendo and Smash fans, you could reasonably assume they'd also invest some of their savings from such a cross-buy package into Amiibo, another major initiative for Nintendo that may prove to be even more profitable than it's games if launched succesfully.
All in all, for Nintendo/Smash Bros fans, there's a lot to be excited for. I think possibly the best outcome for Nintendo is to get fans immersed in all of it. Get them on another new system that offers a wider library of games + get them in a new habit of using Amiibo and put a smile on their face through it all == new profits.
What do you think?
BTW: I think a bundle of some sort using a box like this would be cool....
I predict NX launches in 2017 - not 2016