Bookmark this post and I'll gladly eat crow if I'm wrong about any of this.
There will never be:
Any more themes, basic or special like the 3ds on the Switch.
No Xenoblade profile icons on the Switch
No eshop music like Wii or WiiU on the Switch
No folders on the Switch
No messaging service between friends on the Switch that aren't preselected by Nintendo i.e hello do you want to play?
I wish I was wrong but I know this is the truth. Maybe we'll get some of this on a hypothetical Switch pro or the Switch 2