@gotwriter : I'm pretty sure you are right. They can't let us use the full potential of current-gen since the toyboxes we make are available on all the platforms. If they want to use the current-gen at its full potential, they would have to lock the boxes out of the last-gen console's lists. This could still be a possibility. I'm sure they could do some maths when you upload a box to see if it breaks the threshold of console XYZ.
But my real opinion is that they need to drop support for PS3/XB360. The PS4/XB1 have been out for 2 years now and most of the big games don't come out on the old consoles anymore (NHL 16, Rock Band 4, Batman Arkham Knight, Assassin's Creed...). Those are all best sellers and they are taking it to the next level.
And for those saying that they would lose money if they stop support, think again. Developing for 2 old consoles in addition to the 3 current ones, they are adding a lot to development, a lot to suppost (bug fixes), packaging... There is a big cost part to develop for more consoles. And in addition to that, they have to scale their game down when it could be so much better.