Ports would work perfectly fine and stable on the Wii U if developers put time into it. Thats the thing, for most developers, the time and investment is not worth putting time into. The PS4 is selling phenominally, that means that developers will put more time to optimize the PS4 version rather than the Wii U version. The Wii U may not be as pwerful but it is jsut as capable of having non-glitchy and equal ports. Optimization for each machine is key. You only need to take a look at Need for Speed: Most Wanted, with perfect frame rate, redefined color, and the use of PC textures. This port was done when developers actually thought it would sell through.
tahts right, only if they give the time, which in must cases they dont and tahs the harsh reality, and ubi is not going to give better treatment to wii u than they do for ps4, and if ps4 ports have problems to reach 1080p60fps like assesins creed 4 when you require only 2 to 3x more power than 360 and ps4 is 7.5x more powerful and is as modern as the wii u and even easier to develop for thanks to both the gddr5 and the x86 processor, then why wii u ports would not have problems?
do the math
7.5x more powerful system and more modern gpu can do something taht rerquires 3x more power from a weaker system were the port comes from(was even at 900p at first), ho much poer woul you need to even run it?
1.5 to 2x more power to even run the port at the same resolutiona nd framerate at its counterpartwere the portsd comes
which means that wii u should at least have that much power for even ports to work, cause is not like everybody who ports for wii u gives it special treatment