Now that you have seen the Nintendo Switch do you think it will be successful?

[pokoko]

Not enough information.

For example, will this replace the Wii U AND the 3DS? If so, then it needs to sell in the ballpark of home console + handheld console software numbers.

Pokemon and (probably) Monster Hunter will make it sell more than the Wii U, easily. More than the 3DS? I doubt it.