Isn't that like saying Super NES/Super Famicom was just a NES/Famicom Pro? SNES was a next-gen successor to NES that didn't really reinvent the wheel, other than the games of course. The only reason the controller has several more inputs (shoulder buttons, two extra face buttons) is because of how rapid the industry was changing back then, and Nintendo saw that and didn't want as simple of a controller as NES or even Mega Drive/Genesis. 

PlayStation has mostly changed from generation to generation as iterative, not reinventing the wheel in hardware or controllers. And the aspects that are big changes or gimmicks (PS Move, PSVR) are optional most of the time. 

You could even argue Game Boy Color was just a Pro of Game Boy, and that Game Boy Advance was just a Pro of Game Boy Color. At least by what you're saying in similarities.

And if Switch 2 can cast its image to a screen without a dock or any cords (we should know in April) that will be another way it doesn't feel like just a Switch Pro.  Especially if it can still also display information on the tablet screen itself (think Wii U GamePad but the GamePad is the console, and two screens doesn't require a home console). 

Complete shot in the dark. Well, almost. It’s hard to imagine it selling even better than Switch, so I’ll also pick 120-130M. Which would be a great result.

Fully agree. Think a big chunk of folks will be content with their switch, and with this not being anything revolutionary I expect a decrease overall from Switch 1

Whether a success or not, it's far from a given that a successor will outsell its immediate predecessor.

PS3 sold less than PS2, PS Vita sold less than PSP.

Sega Saturn sold less than Mega Drive/Genesis, and Dreamcast sold a little less than Saturn, but it is really close.

Xbox One sold less than Xbox 360, and there's little chance now Xbox Series will outsell Xbox One. 

Atari Jaguar sold a lot less than Atari 7800, after Atari skipped the fourth generation of consoles.

Nintendo has downward trends for three home consoles in a row, and even after the fluke Wii, Wii U sold less. But Switch is a hybrid and another fluke. But then there's stuff like 3DS selling less than DS.

Suffice to say, tons of hardware sells less than its immediate predecessor. 

Switch 2 will be a refinement of Switch, not as fresh of an idea unless there's some crazy gimmick or feature, they're saving for the Direct. Even if there's a great feature like using two screens (casting to the TV and using a second screen on the tablet), that seems like a refinement of the concepts of Wii U and Switch rather than some industry disruption or huge innovation. 

I just want to say that I think this thread would be better (i.e. more credible) after the April 2 presentation.  We know almost nothing about what games it will have other than Mario Kart 9, and games are a very big deal.

Having said that, I voted 130M-140M (which I may change after the April 2 presentation).  Switch 1 is the type of console that comes around once every three generations.  I really doubt Switch 2 will top it, but I still think Switch 2 will be quite successful.

With Switch surely surpassing 170m at most before 2028 rolls in ( it's already above 150m and will be above 160m by year's end ), I think Switch 2 will go even higher than that in 10 years' time at around 200m. Can't imagine it? Well could you imagine Switch reaching those numbers? Exactly.

Thats the floor for year 1!!

I agree that after w receive more info, this thread will be better. Right now we are just in the rumor and assumption phase.

After the Direct we will vote again.

I think Nintendo understands that its games need to be fun, enjoyable, and be “addicting” in order for the Switch 2 and the games to sell well. There are many rumors floating around about the Switch 2 joycons, the multiple screens, the games releasing. 
Personally I’m happy that Civ 7 will be on Switch 2, this provides a glimpse into what the Switch 2 can do. (We will see if GTAVI will release on it as well).

According to Bloomberg Nintendo expects 20M LTD in 2025 alone. Not even year 1.