Let me start this by saying that so far I love my Nintendo Switch. I think it is a great console and Nintendo really has done a fantastic job with it. You have most probably read all the articles about how it has sold a couple million units in its first few months on sale. That is very impressive and there are some people who think it may shift as many units as the Wii did! While I think the Nintendo Switch will no doubt do better than the Wii U, I do not think it will reach Will level of sales.
Some people say that the Nintendo Wii U failed because of the poor marketing. I think it failed because after the console launched, that first year was just so damn barren for new game releases. It was months before Pikmin 3 was released which was the first big game (and honestly calling Pikmin a big game is a stretch) and the launch lineup was lackluster at best. I think that is what turned many people off the Wii U. Sure by the end of the consoles life it had a tremendous game library, but it was too little too late. The poor battery life of the tablet, slow load times, poor third party support, less power than its competitors, things like this all got out to gamers and after a year on sale, Nintendo was fighting a major uphill battle getting people interested in the Wii U.
It was the lack of software early in the consoles life that really made people lose interest in the Wii U for me. But I do not think that is a mistake that Nintendo is going to make with the Switch. Say what you want about the launch lineup, but in the first year, you have Zelda, Mario Kart, Splatoon a brand new Mario game and many, many other games that look interesting as well. Nintendo has ensured that the first year of the Nintendo Switch's ’life is going to be supported with some damn fine games and that is why I think it will continue to be a success.
This holiday season, kids and people who have been on the fence will be more than happy to get a Nintendo Switch just for Zelda, Mario Kart and Mario Odyssey alone. So while I do not think it will reach Wii level of sales, I do think the Nintendo Switch will be a big hit for Nintendo.