As a more serious note, it still very hard to tell how much a console will sell, but just to guess I could see the Wii U being at 40m worst case scenario and 80m as the maximum. 

I agree with him, and you. I think it will most likely end up at 50M. One only has to look at the launch to see why. Sure, the overall numbers are okay, thanks to the first few weeks. However, if you look at how things are trending, it doesn't bode well.

During Japan's busiest sales weeks, the Wii U was still dropping each week. Europe doen't seem too interested in it. In the US (and EU actually), it is being outsold by the Wii. While some may point out that the PS2 outsold its successor when the PS3 first launched, it's not exactly the same. The PS2 was selling extremely well in the US, the Wii isn't. The PS2 was only 5 years old when the PS3 launched, this will be the Wii's 7th year on the market. In other words, this gen is already dying and people are ready for the next. And while the Wii U is ~$170 more than the Wii (only $30 more than the PS3), the PS3 was a full $370 more expensive than the PS2.

The biggest point here is that price isn't exactly an obstacle for the Wii U. As I pointed out above, the Wii U is only ~$30 more expensive than the PS3. I feel a price cut to $249 will definitely help out its sales, but I don't expect it to be a complete turn around, like it was for the 3DS. Not when the PS4 will most likely be launching for ~$399.

What about the WIi U's positioning makes you feel like it will have mass casual appeal like the Wii again?

I don't expect the Wii U to gather casuals like the Wii did, maybe a couple of games like Wii Sports and the likes could do the job but not the same amount of sales like the Wii did. 

So, does this call for a chalkboard saying...

Wait for:

Game X

Game Y

Game Z

Game Å

or is it a different thing?

Like this one!

Anything below 50 Million would be unbelievable. I see it getting at least 60 Million.

So...how do you expect people to fall for the tablet controllers games if they rule out the need for a tablet controller that has an as many buttons as an Xbox 360? The Wii was a hot item because it had less buttons and simplified the process of gaming for all involved, by reducing it to waggle movement. They can do all that on their IPads. The interest in the novelty of the device comes before the game. I believe the name value of Wii Sports would be the seller rather than the controller itself. The Wii U must have more applications to get the general non-gaming audiences attention though.

Makes no sense comparing the Wii U to the Wii when even Wii itself has lost appeal to chance-upon-gamers. The fad genres come and go. Wii U's design is intended on delivering a new experience to gaming. I like it and my kids , in a household that openly condones and encourages gaming, skip over PS3-Xbox360-old Wii-DSs-iPads and want to play Wii U everyday. The 5 year old for the first time can meaningfully participate, in even more depth than before, by calling himself the Block Captain in Super Mario U. He helps out by setting blocks, stunning enemies, and his new found love of alerting his brother of the wherabouts of "3 ups!" which he can see on the gamepad.

The only other game the 9 year old gravitates towards is Minecraft, talk about an ugly game with appeal.

Wii U is a damn hard device to market effectively, just like the 3DS. But I'm still optimistic that Wii U standing on the shoulders of the mighty Wii will be the 2nd best selling home console of Nintendo.

i think the wii u will sell around 65 million in its lifetime

The Wii U still uses the normal Wiimotes, so the simplified games like Wii Sports, Just Dance and the likes will stay (plus whatever things you can do with the Gamepad, although those will be optional). They will surely decrease in popularity, but if the devs want they can still make those games for the Wii U (Ubisoft already did with Just Dance 4).