Lets make it very simple
1. optimisation : it can make a huge diffrence interms of framerate, quality and resolution, a good example is PES 15. Fox engine isnt optimised for Xbox one resulting in a resolution of 720p compared to 1080p on PS4.
2.Computers are running much higher specs, here is what i mean
Wii U has 2gb of ram and 32mb of esram. it runs arkham city (with very little optimisation ) at 720 30fps. the computer which is running the game with 1080p probably has atleast 4gb or ram and a core i3 processor which is 4 times more powerfull than that of ps4 and xbox one.
3. the game was intended for limmited number of systems and the Wii U version was just and xbox 360nwith diffrent UI.
4. even the game is not running well on its intended systems. here is quote from Wikipedia"
Technical issues
During launch week, issues were found to exist in the code-restricted content. Some customers discovered the code to be missing from their copy, preventing them from obtaining the Catwoman story missions. The problem was reported by customers in Canada, the United States, and the United Kingdom. Warner Bros. issued a statement claiming that the missing codes had affected less than 0.5% of customers.[227] Upon release in the United Kingdom, a technical issue rendered the game unplayable for some players, booting them from the game with an error message that the "downloadable content is corrupt." Rocksteady European community manager Sarah Wellock claimed that the fault lay with the PlayStation Network and Xbox Live online systems.[228]
In early November 2011, Rocksteady confirmed that it was investigating reports by numerous users that save files for the Xbox 360 version of the game were being erased without prompting, resulting in players losing their progress and being unable to complete the game.[229][230] On launch, performance issues arose for the PC version when DirectX 11 features were enabled; the developer acknowledged the inconvenience and recommended to run the game with DirectX 9 while a title update was released to address this matter."
if you want more . Arkham city runs terribly on my PC which has an amd 9590 CPU and GTX 970.