I'd still prefer two devices: A home console and a handheld that share the same OS and play the same games at different settings (cartridges instead of Blu-Rays, Cross-Buy, Cross-Play, one account for both devices). It would be way more comfortable for the user to just pick the product he/she likes instead of forcing people to buy a tablet.
The tablet sounds like a huge compromise to me and would be expensive for a handheld console. If Nintendo makes two devices instead, a home console and a handheld, they could have a home console as powerful as a PS4 that's really small (no Blu-Ray drive and no physical hard drive!) and sell that for $250-300. The handheld could be $199 at launch. Get a free game if you buy both machines. But I guess that's just wishful thinking at this point.