It's 'current gen' in terms of performance because everything else blows it out of the water in that regard. It's not 'current gen' in terms of hardware features.
Resolution is the most demanding aspect of GPU performance. 1080p demands 2.25x the performance of 720p and 3.4x the performance of 600p. Xbox One games that run at 1080p should therefore
theoretically be possible at 600p on Wii U on those occasions that CPU and memory size differentials aren't an issue and tessellation is kept in check. Just contrast these
Crysis 3 comparison shots and tell me you see a huge difference between 'very high' and 'low'. There's little visible difference but I could easily picture Wii U playing it on 'low' at 720p with Xbox One getting 'high' at 1080p and PS4 getting 'very high' at 1080p.
It's relative and game based is what I'm saying. The performance differential between 'low' and 'very high' in that game is absolutely
immense.