On the off-topic of the next console. If Nintendo were to release a new console for the sake of reversing diminishing sales, then they're potentially missing a big opportunity. What I mean is, how do we even know that they have the console they want to release, ready? Sure, they probably have a backup-plan console that could be released at any time, but this console would never match the sales of Wii. What I hope is the determining factor, is when the tech they want to take advantage of becomes viable for mass-production. Just like with 3DS, they've been holding it back until the tech was ready to bring to market.
Now since the Wii has reduced the competition to such a pathetic state, and because of the lack of foresight in PS3/360, Nintendo has the opportunity to wait until they can get the next console 'right', again.
Besides, they already have 'a new console' that they haven't fully exploited: Motion+! Depending on how well Zelda+ does, Nintendo might not have to release a new console for several years.
And on a personal note, I would be very disappointed if the only upgrade was better specs.