>> What mirrorless cameras giveth to the lens designers, digital sensors taketh away...
It sounds right. Comparing Contax SLR vs. Contax G, Fujifilm Xpro-1 system vs. Canon T4i/5D system, with the limited lenses I tried (Contax : 28,45,90,35-70 zoom; Canon/Fuji: 28f1.8,50f1.4,85f1.8 vs. 18f2,35f1.4,60f2.4) the SLR look better in IQ, and the price is clearly on the SLR side. For about $3200, I have the choice of Fuji Xpro1 + 35.1.4 + 18/2.0 + 60/2.4 or Canon 6D + 50/1.4 + 28/1,8 + 85/1.8. But Fuji-X is APS-C while Canon is full frame. Canon has a lot of room ready to expand but Fuji-X is still hard to say.
But in the long run, potentially, will Fuji-X eventually offer a better IQ system?