It is so far from the best media consumption console (or streaming console - as if I'd want to stream 480p video to a fucking tablet. It's 2015, not 2006) that i have trouble imagining this isn't sarcastic, despite having read the detailed OP a few times.
I mean...
1. The controller is the remote.
The wiiU's handy dandy TV button let's you use your gamepad as a universal remote and turn the tv up and down, change channels, and power on and off without ever letting your hands leave the controllers. You can then launch your apps with the same device no switching.
Much of this can be done using XBO, and better.
2. Support for the "Big 3".
Amazon, Hulu, and Neftlix. Between these 3 services you basically can watch every big TV series and movie ever conceived. It also has Crunchyroll for anime fans.
Both PS4 and Xbox One have support for these sorts of things, plus like support for five trillion other services which
actually make them far closer to the claim "you can watch every big TV series". Only in the case of PS4/XBO, it'd be "movie, anime, tv show, web series, web magazine, sports game, pornography, etc."
Advantage: The consoles not named Wii U.
3. Off-TV play.
Or should I say watch? You watching an episode of Cut Throat Kitchen and your brother/mother/significant other wants to watch something else? Just flip it to the gamepad and keep going not only has dedicated speakers but a headphone jack to keep from disturbing your significant other.
I mean if I was going to do this, I'd just use Vita or one of the tablets to stream XBO or something or whatever because I'd rather cut my own wrists then watch TV at 480p on that grotesque screen. Once again, it's 2015, not 2006. Nintendo couldn't even do the feature right.
4. Web Browser
Finally, the wiiU has a fully functioning, intuitive, powerful, and robust web browser. You can suspend any of those aforementioned streaming apps and launch the web browser at any time to look up random stuff about what you are watching, find youtube videos (youtube app sucks use the browser), or pull up more media on various sites all on the TV/pad all while your app is comfortably suspended and can be relaunched at the same point without missing a beat.
It's not even robust or powerful, but I mean sure it has it. And it's probably better to control than the XBO or PS4's version due to the tablet controls. Buuut that's about it. And this relatively minor advantage (considering PS4 and XBO also have web browsers) are massively offset by ya know the sort of important thing of
not playing DVDs or Blu-Rays. Not to mention with DLNA and all that now you can basically turn the XBO/PS4 into the ultimate all purpose media consoles.
Basically the Wii U could only be considered the best media/streaming console if you have zero exposure to others or you're just being intellectually dishonest (that is to say, you're arbitrarily excluding the advantages of the competitor so as to force the audience to conclude Wii U)