That sounds quite reasonable as far as rumours go. However one thing I just can't get my head around is the lack of an optical disc drive, just why? I really don't understand, are they too expensive for Nintendo now in this authors fantasy land? Games just sell more at retail than they do on the eshop, it's just a fact. I'm sure Nintendo could give consumers the option to go digital only with a cheaper sku, but to force people to get N or get out just seems like suicide and goes against what makes Nintendo Nintendo.
The piece of evidence that damns this for me though is backwards compatibility, I would not be able to accept a reality in which Nintendo goes through the tremondous monolithic amount of effort and money to make the NX backwards compatible with Wii U, but you can only play your physical games through the use of an external optical disc drive. Hahahahahahah no.
On another note I think the hand held being replaced before the console isn't stupid. The 3ds came out basically 2 years before the Wii U came out, plans get set in motion and schedules are planned out years in advance. It's not as simple as "Oh no we need a new console, better stay up and design one up overnight!" Nintendo would have realised that the Wii U was a failure and beyond saving around December 2013, if the theoretical NX console isn't ready before the theoretical NX handheld then there is nothing they can do about that.