I mean, there's a few things that I could class as pet peeves, just a few being;
The lack of an internet browser, YouTube or Netflix. I'd love to watch YouTube or Netflix while on the train instead of on my phone, bigger scree and I can sit it up on the table.
The stand itself doesn't give me enough confidence to sit the console on a tabletop without falling over, as it's happened a few times already, would be nice to see a later revision have a more balanced stand, although I could easily just buy a stand I suppose, lol.
I know it's pushing out a lot of power while in handheld mode, but the battery life is a lot weaker than I'm used to, thankfully I have a powerbank I can take out with me though.
There are many more examples, however I'd feel like I'm just nitpicking, since regardless of these things, it's still a great console and unlike my Wii U, I don't regret buying it whatsoever!