Will a i5 2500k bottleneck the new GTX 1080


This, although even the 4690K bottlenecks my 980 in certain CPU heavy games like BF4 and GTA 5 (144hz). It's unlikely it will bottleneck at less than 60 fps in new games any time soon though.
 

The second gen is quite a bit different from the first gen but I feel like your statement isn't true, what games are you playing and what are your CPU and GPU usages while playing.