Shooting wide open is fashionable because it’s a sign of expensive gear. Once artificial bokeh is perfected I expect people will stop obsessing over blurry backgrounds.
Agreed on the shots where you're at 1.4 and pushing the limits of your shutter speed.
DC stands for “defocus control", as distorting the bokeh forward of backward.
How do you feel abbout the DC function? I've found R settings don't really focus correctly with AF, so it's best to focus manually. Is that the case with the 135mm version too?