~100 million, basically the combined sales of 3DS+Wii U+Vita.

No less than 100M, but no more than around 125M. Assuming it's basically just a more powerful Switch and not much else, the only way it doesn't make it over 100M is if Nintendo either A) charges way too much (like $500), B) they somehow botch the marketing, like Wii U marketing bad, and/or C) they don't a major software drought in its first year. I suppose in such a a worst-case scenario, maybe 70-80M. Nintendo's handhelds have never outright failed, and I doubt their hybrids ever will, either.

It will probably outsell even the Switch in the long run

The form factor doesn't need to change. It should be max 1440p docked and 1080p handheld with graphics equivalent to Xbox one x or PS4 pro and have battery life between 8-10 hours. They can keep everything else the same..

I can easily imagine the floor being 100M if the Super Switch is simply to be an upgrade without much added bells and whistles to the successor.

Although if some hiccups for whatever reasons(Marketing, software problems, going back to separate Home console/handheld buisness), maybe it could go as low as 80M.

I don't imagine it going down further

Depends on the pricing and what it brings to the table. I'd say that with an hybrid system i can't see it do less than 60-70. 3DS had everything against it and still managed to do 75 millions. But 60 millions is the floor if it is badly marketed, games drought and high pricing.

As a Nintendo home console fan I can’t remember a time when I had so much optimism about the future for a system. I am confident in Nintendo, the developers (they’ll all be on board this time), the fans (they support the quality Nintendo and 3rd Parties have been producing), and the mainstream to help keep this ecosystem alive. Nintendo May squander this good will (anything can happen) but for at least the first 2-3 years we’ll be eating well with the Super Switch (which is what I hope they call it.)

I’m going with 51-60 million, and that assumes a terribly botched launch, flagging developer support, lackluster 1st Party outings, and the fact that they call the successor “Switch Me.” I don’t believe any of this will happen, but even if it does that should be where it all ends up.

Anything below 80 million should be considered a failure, given the success of Nintendo handhelds and the success of the Switch.

Too many unknown factors at this point. But people saying no less than 100 million are forgetting just how bad a console company’s fortunes can change generation over generation.

If Nintendo releases the Switch with minimal upgrades, it likely won’t fall completely flat, but it’s going to sell fewer units than Switch 1. If it comes with a new feature that backs a killer app, then the potential grows considerably - this happened with touchscreens and motion controls in the Wii and DS generation. But Nintendo has been known to make stupid moves in the past:
N64: cartridges - that hamstringed the console against the PSX which could get much larger games on the console for a much cheaper price to the developer/publisher and consumer. This was a massive stumble because Nintendo was synonymous with video games in the later 16-bit generation. Neither Sony nor Sega had a particularly stellar launch of their 32-bit consoles. PSX took off because Nintendo fumbled the N64. And PSX’s dual shock stole the thunder of arguably the N64’s best feature (analog sticks).
Gamecube: PS2 except missing vital features - mostly the console was an imitation of the PS2, except with a less usable controller, smaller media, missing DVD playback, and less aesthetically pleasing.
Wii U and 3DS both suffered a similar problem: the new features didn’t make games simpler, didn’t yield many ideas from Nintendo themselves. Both consoles felt outdated at the time of release, and without a killer app (like a Super Mario Bros, Wii Sports, or Mario Kart 8 Deluxe/Breath of the Wild). On 3DS’s side, the 3D feature was hit heavily by anti-3D marketing from tabloids - I don’t think it’s unfair to say that outside and uncontrollable circumstance damaged the handheld’s potential. I don’t think it’s likely Switch 2 will have a feature that terrifies the tabloid spinners. But the amount of seizures the 3DS caused is likely less than Pokémon.

Where Nintendo does well is when it packages greater complexity into more simplistic interfaces and features. The NES did this with two action buttons and a D-Pad, the SNES took on arcade complexity and perhaps improved on the design by adding the diamond face buttons and shoulder buttons. The N64’s analog stick for 3D was a great idea too for simplifying and improving 3D movement (but cancelled out by the cartridge thing). The Wii and DS added motion (IR, accelerometer, and later gyro) and touch controls which simplified gaming further and added some complexity at the same time, and all in a very entertaining way. The whole Switch concept greatly increased the convenience of handheld/home console gamers like myself while at the same time being sufficient for those who handheld games only or home console gamed only.

What comes next? That’s the multi-billion dollar question. Almost everyone has opinions on that. There are a lot of different possibilities.

The other thing is the fact that Nintendo often underestimates the potential of their own ideas, and other companies end up picking them up and running with them much further than Nintendo: casual games, touch screens, and fitness applications. And it’s not a situation where Nintendo tried and failed, Nintendo tried and succeeded with these concepts, but then abandoned them or scaled them back. So, we can’t underestimate Nintendo’s potential to abandon the golden goose before her chicks hatch.

There are too many factors to consider right now. Perhaps after some revelation about the console.

I honestly think ~100m is the floor unless they opt for a shorter generation and that doesn't seem to be the trend these days, with the success of the switch and years of pro/successor rumors the sheer amount of people looking forward to what Nintendo does next right now is probably unmatched in their history. Obviously if they screwed up really bad that would change things, but I think they'll play it relatively safe this time around and many, many current Switch owners will want the new system by default.

I don't think this is a reasonable question until we actually see the Switch 2, but I'm thinking that assuming a relatively conservative hardware upgrade and some declining interest in Nintendo franchises, they should still reach 80 million, assuming a similarly long lifespan of over 6 years.

I'm EXPECTING higher figures, but we know jack ****.