There was another thread... maybe not on this site... that showed the historical versions Nintendo has done over its portable life and 2014/2015 should contain some sort of 3DS revision while 2016/2017 will be the successor.
Though I honestly can't think of what they'd revise. They have a pretty great physical styling for hte 3DS, have a larger XL and they have a 2DS for those who are younger or simply don't want clam shell design.
I'd bet 3DS (2015) would simply either be a model with better battery life and/or continued variations on colors and unique IP related skins.
It wouldn't make sense to really do anything else, unless it was another 2D variant with a clam shell format. But that seems silly as you can just turn off the 3D for the same effect.







