I just find crazy how people could say this without all the info and more important, info about the games, that's why we buy consoles, games.
Problem is that when it comes to "games" WiiU had all those Nintendo games and a relatively successful new one in Splatoon and look at how much the WiiU sold in spite of those games.
When it comes to Nintendo consoles, it seems like Nintendo's best case scenarios are reduced to doing something that will attract people who would otherwise not buy consoles, and that doesn't seem to be the case with the Switch.
The precedent dictates that if Nintendo doesn't accomplish what they did with the Wii, then they are destined to remain on the shadow of Sony console-sales-wise.
The thing that the Switch does have going on for it though I admit, is the promise that those handheld games from Nintendo will be on it, so you will have to buy Switch for Pokemon Fuschia, Monter Hunter, etc.
You're right that Wii U had some great games, one of the major problems though was that they were too far and few in between. It has not been uncommon to go 3-4 months in between big releases on Wii U.
Quality wasnt an issue but quantity certainly was, 3DS had a pretty good mix of quality & quantity and since Switch will be a successor to 3DS & Wii U than its possible that we could be looking at a device with 3DS level software output & Wii U level software quality which would make for a very appealing device.
As long as they get the marketing & price right than they should do pretty well.