League Display on Retina Display
Yeah, it's a tad blurry when I use League Display, after some (really easy) digging it turns out most of the art is 1920x1200 whereas the Retina display is much higher than that.
On one hand I feel like League Display should offer higher resolution for higher resolution displays but on the other hand I know Riot doesn't really like to release full resolution artworks, only 20% or so can be found on the online Asset Kit but that's about it...