Not sure if it will be really successful, still too many questions :
- For the non-gamer audience : zero interest. It can't attract the Wii crowd.
- For the PS4/One gamers : really limited interest, and even less if they can't get games like RDR2 or COD. If the console isn't powerful enough, it will be really complicated to get the big 3rd party games, especially is you have to create a handheld version of your game. Could be a Wii U 2.0 for this audience.
- For the PC crowd : maybe as a complementary console to play Nintendo games, but it was the same thing with the Wii U and it didn't set the charts on fire.
- For the 3DS crowd : it will depend on price, autonomy, games and practicality. We need to know if they can make a cheap, powerful handheld with a good autonomy. The practicality doesn't seem really good (too big), and it needs to be at least resistant to attract kids and their parents. It doesn't look like something you'll put easily in your kid's bag before leaving the house, so we'll see. Right now, there is no reason to buy a Switch if you or your kid has a 3DS. So the hardest part here is to kill the 3DS and attract the future former 3DS players to the Switch instead of the tablets/mobile. They lost a lot of players in the DS/3DS transition, it won't be an easy thing to do, it will depend on the qualities I've listed earlier.
- The Nintendo hardcore gamers should be on board, but this audience is a lot smaller than the others, as demonstrated by the Wii U.
So, with the information we have now, the Switch shouldn't become the leader of the gen like the Wii, but could have an average success (better than the Wii U) if they succeed in the 3DS/Switch transition. This transition is not assured yet and will depend on the future information we'll get (the real news). Same expectation as yesterday and 3 months ago, the information we got today is exactly what we already knew after all.