^ Regarding AR on the 3DS, I loved that and played a ton of Faceraiders and these minigames with the cards, but mostly Faceraiders. It was a lot of fun.

Analog stick of the N64 or the exchangeable games feature of the Atari 2600.

Those are probably the ones with the most staying power.
Motion controls could have been something great had they been utilized more.

From the options, it's not even close: motion controls. The hybrid nature, awesome as it is, doesn't affect gameplay experiences per se. Motion controls changed the way we would perceive playing a game and it's a shame that it lost the battle to the more "traditional" style of gaming. But if VR keeps improving, it will play an essential part in that.

I wouldn't say motion lost out as it's more of a supplement than a replacement for buttons and sticks, and it is still alive and well today, coming up on two decades after the launch of the Wii.

The Switch, currently the most successful platform on the market, has motion capabilities as one of its core features, and they're used in practically every first party game and many third party ones as well.

I'm totally with you (as pretty much always, my friend!). I just meant to say that, nowadays, it is not like you have many mainstream games being developed from the ground up for consoles with motion controls as the main control feature (even if I know Switch Sports is actually a thing). It can happen for smaller mobile titles, but you are not getting the same amount of experimenting that was happening back in the Wii days. I miss that!

Hybrid, easily. It's not a gimmick like the rest. And even then, the Switch still has gimmicks for those that want them (JoyCon motion controls.
Dual Screens, 3D, and the second screen were all cool and I wish more was done with them.
A lot was done with the Wii's motion controls, I just prefer playing without them or having them more subtle in a standard controller (gyro aiming).

True, I miss that as well, it was super cool to get experimental motion stuff back then like in Metroid Prime 3, Red Steel 2, Zack and Wiki, Medal of Honor Heroes 2, etc.

Still, I'm just happy motion controls are still around and thriving on the Switch, whether it's aiming my bow in BOTW, shooting demons in Doom Eternal, exercising in Ring Fit Adventure, or spraying ink in Splatoon. I really enjoy them so the fact they seem to be here to stay is nice.

Motion control was the coolest and most interesting feature. Though I think at this point we can agree there are only a small subset of types of games where it is really useful and makes a big positive difference in the gameplay. Most Wii games just ended up tacking on 'waggle' controls to make use of the motion controls when it wasn't really needed. As we see on Switch, few games actually use motion controls, though I certainly wouldn't want motion controls to ever go away. I would actually like to see a bit more use of motion controls in Nintendo games in the future.

But I'd say hybrid play is the most important hardware feature they've introduced. I can't imagine ever owning a system in the future that doesn't allow me to play both handheld and on a TV. And with handhelds always being the stronger sellers for Nintendo it clearly is the natural endpoint of Nintendo's system design to make consoles that are also handhelds.

Dual Screens was a cool side thing for the industry. And obviously making it with 3D vision was a cool addition even if it was an unnecessary fad and pretty awful in terms of a business decision. Ultimately dual screens was just a side avenue and was never gonna stick around but still a cool feature.

So I guess I'd say hybrid is the most important HW feature, but motion controls was the most fun and interesting feature that really changed gameplay while it lasted.

Motion controls haven't gone anywhere, they are alive and well on Switch, and many games use them.

Looking at the more noteworthy Switch titles, they're featured in BOTW, Mario Kart 8, Splatoon 2 and 3, Monster Hunter Rise, Super Mario Party, Switch Sports, Mario Odyssey, Mario Tennis, Mario Golf, ARMS, Pokemon Let's Go, Ring Fit Adventure, Luigi's Mansion 3, Hyrule Warriors Age of Calamity, Doom 2016, Doom Eternal, Wolfenstein II, Overwatch, Fortnite, Skyrim, Paladins, the list goes on and on.

Almost all good shooters have gyro aim. The Sniper Elite games are another example.

Gyro aim is the most widely used way of implementing motion controls.