I honestly want to see what Nintendo comes up with. The Switch is over three years old. And, they tend to run on a five year console cycle at Nintendo. Which means we are getting towards the fourth year of Switch when these are out.
Graphics and performance wise, The 3DS was like a portable Nintendo 64, and the Switch kind of feels like a portable Wii. I imagine that their next console will probably have graphics and performance similar to the PS4 Pro, or the Xbox One X. Since they always seem to be about a generation behind in specs, but they are usually just powerful enough to have passable ports of games being released to the more powerful consoles and PC. I would personally like to see them keep supporting the Switch as a handheld, when they release a new Nintendo console. As the life of a Nintendo handheld seems to be double that of their standard home consoles. I know Nintendo keeps denying a Switch Pro, but as we have seen in the past, Nintendo is always remaking and powering up it's handhelds. And, since they removed features to make the lite, it might be interesting to see if they would add more things to a pro version.
LOL!!! The Switch is WAY more powerful than Wii. It's more powerful than Xbox 360 or PS3 so how in the world are you comparing it to Wii graphics?