Epic isn’t planning to bring the Unreal Engine 4 to the Wii U. The news isn’t really a surprise, as Epic has said all along that Unreal Engine 4 is targeted at the next generation of consoles. Titles, however, could be back ported from the Unreal Engine 4.
Sources indicate that Unreal Engine 4 titles that are ported back to the Wii U would likely be done using the Unreal Engine 3, which Epic already has running on the Wii U. A number of titles that have already been announced for the Wii U, including Arkham City and Alien: Colonial Marines, for example, are powered by the Unreal Engine 3.
If you look at all of the clever wording it is obvious that Epic is saying that the Unreal Engine 3 is a better fit for the Wii U platform; but the fact that a title using the Unreal Engine 4 could be ported over to the Wii U using the Unreal Engine 3 is significant because it means that Wii U could still get those titles.