All of this isn't an issue if you use stick controls, of course. But if you use stick controls then you've got an even bigger concern.

What's wrong with the d-pad?

EDIT: You mean this? http://www.ateijelo.com/blog/2017/07/12/effective-fix-switch-pro-controller-dpad-issues

Nah, don't get me wrong. There's absolutely nothing wrong with playing in handheld mode, except, you know... everything. Especially in Splatoon - other games I can understand, but seriously Splatoon? Like, dude. How do you even do that? When I played through the campaign (all of it in handheld mode, because I was at a friend's with other people and no one wanted spoilers) it was so jarring and downright impossible to play like that I ended up just doing tabletop mode all the time even when it shouldn't be possible - like, stacking up boxes and stuff just to get the console on a decent position so I could play with decent controls.

I mean, it's not just a taste thing. Splatoon on handheld mode is objectively crappy, because it only lets you tilt the console so much upwards before it stops resetting the camera proper - and the height it was set for is the height you'd normally use any controller (without a screen) on, so that means you're the one who needs to look down at the game instead of the game's camera being adjustable for your needs. In other words, playing on the bed is pretty much impossible.

All of this isn't an issue if you use stick controls, of course. But if you use stick controls then you've got an even bigger concern.

Yes, that's how you're supposed to play.

What I'm talking about is, if you're playing while lying in bed, for example, you're holding the Switch upwards, so the camera moves up too. Since you don't want to play looking at the sky at all times, obviously you press Y to reset the camera, and... nothing happens. You're still looking at the sky, because for some reason it only resets the camera horizontally after you tilt it so much. This has something to do with how the game was originally never programmed to be played like that (you'd never hold the Gamepad upwards on the Wii U), I guess, and it's a pretty big issue in handheld mode. Even holding the Switch in front of me while sitting down was a little bit off, I had to constantly look down at it.

...well. Unless, they fixed that in an update or something. I wouldn't know, because I only played at launch.

It's true, I did forget that option.

So when you have the option to play Switch on your TV, you'd still prefer to play it undocked?

While I think undocked is nice and convenient, whenever I have the option I'll definitely use my TV. I feel most games run a bit better when docked.