They can't change the CPU/GPU architecture without breaking compatibility with existing games, we'll probably see a mid-cycle refresh with higher clock speeds and/or more CUDA cores down the line.In more than two and half years (just under 3 years) is my guess, expect a New Switch with a custom Pascal chip, 4K and a better battery by end on 2019.
For now I'm just excited for upcoming games announcements, E3 2017, new system updates (more OS features) and software/apps (web browser, YouTube, etc...).