It's all about tastes and preferences.
The PS4 has twice the amount of retail releases (if not more) than the Wii U does, but the Wii U has more software that I'm interested in, so it's a bit difficult to make big sweeping statements objectively.
Well..yeah. That's the problem. The PS4 has every genre under the sun, as opposed to the Wii U which has a very limited selection of games. It's not just open world, either. What if you want to play WRPGs? Story-based episodic adventure games like Life is Strange? Hell, it took them three years to give us an actual JRPG. Saying that you are SOL with the Wii U unless you like certain genres is spot-on.