I don't think it matters too much, but launching early has almost always been preferable. The key is that the system is desirable to either non-Nintendo core gamers or casual gamers or both. With their current state - and barring a Wii U turnaround - it has to be really thought out and can't be simply a new console release. My plan would be:
-Release an iPad mini sized tablet/handheld hybrid next year. Powerful and cool, it will eventually link to the new console. It's pushed hard to a wide audience. It will have a great ehop and virtual console and online games, but have a paid subscription service.
-Develop a powerful console at least 3-4X the PS4. Controllers work through wifi and the tablet can be a controller/second screen. Up to four tablets can link with the console. It will launch at a high price point with an online subscription, but be promoted as a premium product that even XBOne or PS4 owners would envy. Call it NES2 to trigger some nostalgia in older gamers and promote a back-to-basis approach.
-Buy or hire a couple solid devs to start the software now for the console's launch. There needs to be a key launch title in place for the core audience that builds hype: I would develop a massive game that implements the previously launched Tablet heavily to form a unique experience. My game would be something set in the Metroid universe, but all new in title and theme. Perhaps involving a group of 4 bounty hunters (one of which could be Samus, but the others just as important and unique) traveling back in time to recover an artifact and fighting a mix of aliens and dinosaurs. I would hype it by releasing 4 classic side-scroler adventures for the Tablet in advance, telling their back stories. Then the massive NES2 launch title would come out and be a 1st/3rd person 3D shooter with all four characters. Multiplayer could be played using tablets and the NES2 (or just the console) and competitive online multiplayer would be awesome.
-A second launch title would be a Wii Sports type title that would again incorporate multiple tablets. A unique version of games like pong could be played in a living room using motion-sensing tablets and an augmented reality through the screen. You would physically move the tablets and bounce balls back and forth and the overall action would be seen on the TV. This could possibly be a pack-in.
-Also ready for launch would be Super Mario Galaxy 3 (for some Wii generation nostalgia), Last Story 2 with online or Tablet based multiplayer, and a Shin'en developed F-Zero.
-Key 3rd parties like COD, GTA would be courted and possibly paid for ports.
-Traditional Nintendo franchises would follow as the price of the NES 2 was lowered over time and a more casual audience is targeted.
So this system could launch any time after Wii U has been on the market for 5 years. The key though, is that the system and its games are truly ready. If you don`t have several key, must-have groundbreaking titles ready, delay until you do. Simple as that.
