Well, honestly if the Unreal Engine is usable with current generation. Even if WiiU isn't a huge leap, it should be enough to use the next engine, unless the bare minimum requirements for the engine are going to price the majority of PC owner out of the market until they upgrade their computer.
Ok, that isn't exactly fair, I know that the gaming PCs are much better than the current generation systems...and are probably already at the level of what the next generation consoles will be...but that is kinda to be expected. computer systems can be modified and upgraded every year, but consoles can't.