Wii U is an HD console though... I don't agree with your global predictions. Wii U lowest is too low, and the highest is too high. PS4's is too high altogether. Xbox One's is too low.
I agree that WiiU is an HD console, so the abbreviation is nothing but a convenience from the previous gen. I am a bit puzzled when you say, "Wii U lowest is too low, and the highest is too high", which kinda negates itself. This is a range, and as long as your estimation is something in between, it means you agree with it. However, the variation (the given range) might be too high, which is becase It is very nebulous at this stage what the market share between Wii and the 2 true next gen consoles will be (80%-20% vs 90%-10%). There are two major reasons for this:
a) The Japan Effect is yet unknown, but should be unfolded sometime after the release of PS4 in Japan
b) Whether or not the effect of WiiU Touchpad is a fad is unknown.
As for the XB1 and PS4 estimations, again, the usual reaction to my estimates, which turn out to be all true at the end of day, but here is the reasoning...
The low ball estimate for XB1 assumes 80% market share for HD Consoles + 24% Share for XB1 vs 76% for PS4
The high ball estimate for XB1 assumes 90% market share for HD Consoles + 33% Share for XB1 vs 67% for PS4
The low ball estimate for PS4 assumes 80% market share for HD Consoles + 33% Share for XB1 vs 67% for PS4
The high ball estimate for PS4 assumes 90% market share for HD Consoles + 24% Share for XB1 vs 76% for PS4
In either case, we assume the market size is constant. And let me add already that you WILL BE AMAZED by how accurate those estimates will turn out to be over the long term. Just keep watching!
* This is not wishful thinking; this is scientific reasoning & estimation.
Regional Analysis (only MS and Sony Consoles)
Europe => XB1 : 23-24 % vs PS4 : 76-77%
N. America => XB1 : 49-52% vs PS4 : 48-51%
Global => XB1 : 32-34% vs PS4 : 66-68%