Why is it a horrible console?
Well, at least I will give you my opinions in this aspect.
The Wii U is not really horrible, but the lack of software makes it a PITA.
Also the gamepad was a bad idea, it just isn't nice. A control system that would be uniform so that every player uses the same (like classic pro game controllers or wiimotes) would have been better.
Of course you can just ignore the big piece of cumbersome controller and let it collect dust while you use pro controllers or so.
The Wii U online services are bad, but at least they are not classic Nintendo bad.
The hardware and graphic capabilities are OK, and the size and power consumption are great.
A normal user will need a bigger USB HDD, and the lack of power in the USB ports that makes you either use two ports for an external unpowered HDD or use additional power adapters and cables for an powered one is... stupid... hell, the Wii was able to handle the required power.
TL;DR: The only thing that really makes the Wii U horrible is the awful lack of game variety and quantity, and the very bad PR that Nintendo is doing that makes you believe that they will not support it strongly anymore (perhaps that's just in my head).
PS: And the lack of a Metroid game, yes, that makes it horrible.