Given how bad Unreal engine 4 looks on PS4, does it even matter?
Who is going to use UE4 anyway? EA has switched to Frostbite 3.0 (no Wii U support atm), Square has got Luminous engine and Glacier engine 2.0, id has id tech 4, Activision have their own engine, Ubisoft loves Nintendo and will support Wii U with whatever engines they have (Dunia, Watch Dogs one etc). Epic themselves will probably stick with Durango exclusively....Who else is left?
Wii U might miss out on a few niche UE4 titles...I think the main problem right now is Frostbite 3.0, Nintendo needs to talk to EA about that