2024. no reason to rush. It is doing great, no signals of sudden dying (like wii), and nintendo themselves said they want a long switch life.
As my bets for it:
-PS4 like visuals on 1080p 6"screen. Less bessels, so smaller then current switch.
-An addictional version will also be sold. A foldable version. Regular size as the base version when folded, bigger screen size when unfolded. When semi folded, allows 2 played tabletop, each facing each other, looking at is own side of screen.
-2 Dock versions: a mini regular dock that just streams to tv, and a 4k dock that uses deep learning to generate a 4k image from the 1080p input (Similar to DLSS in new NVIDIA rtx boards).
-full BC.
-now joycon models that change form, the handle opens in 2, and allows better ergonomy in either modes (I wish I knew to draw).