I always forget that BotW released on the Wii U. 

Easily Wii U right there because of better exclusives, even though they couldn't save the trash hardware.

Xbox One. It had better graphics, larger game library... And definitely a more important 2nd and 3rd party game catalogue.

If the WiiU didn't have one of my favorite games ported over to the Switch (Breath of the Wild) it would have secured my vote based on that game alone.

Better in your opinion, which can be which you enjoyed more personally or which you think is better based on other criteria, whichever you prefer or is more applicable for you.

This is a very close one for me.

The Xbox One does have some excellent games like Doom 2016/Eternal, Witcher 3, Hellblade, Ori and the Blind Forest/Will of the Wisps, The Outer Worlds, etc.

On the other hand, the Wii U had BOTW, Bayonetta 2, Tropical Freeze, Mario Kart 8, Splatoon, Mario 3D World, Captain Toad, Pikmin 3, Fatal Frame 5, Xenoblade Chronicles X, etc.

The latter actually convinced me to buy one so it has that in its favour, though I did end up being disappointed with it. Meanwhile, Xbone never managed to sway me as almost all the games on it I'm interested in ended up coming to Switch.

Having a gaming PC means that any Xbox becomes redundant. Not so much with Nintendo consoles, and especially the Wii U. So it's the Wii U almost by default already.

But to the Wii U's credit, it has a ton of great titles, from Mario Kart 8 over Hyrule Warriors to Splatoon and NES Remix, it has a ton of games that should have been great hits, but the low install base of the Wii U made that impossible.

One could argue that most of its best games being available on Switch makes the Wii U redundant. (Though I personally don't consider it so)

Almost all Wii U games are on Switch, Wii U is even more redundant than Xbox One, as Switch versions comes with portability, motion controls, etc. Not to point they are generally enhanced versions with DLCs and whatnot 

All XBox One games are on Series X, so XBox One has nothing?

Obviously this was about comparing the two consoles in their prime, before the successors launched.

 If the argument is exclusivity defines whether a console is redundant or not, then yes, Xbone became redundant in the moment Series X launched 

There was no reason to get an XBox One, while there was a reason to own a WiiU. Admittedly not a big one, but it was there. So, WiiU.