I use the 35/1.4 L mostly (only) when I need the extra bokeh or extra light (courtside sports/indoors no flash) c/w the 16-35 or 24-70 zooms, though I feel images are pretty similar in quality, so it is more of a speciality use for me. AF is just a touch slow.
Likewise the 50/1.4 only gets pulled out for specific shot requirements, though I am loving the classic FOV of the 50 with the FF sensor, and I use it much more now c/w my time with the 7d. I too, am considering the 50/1.2 to complete my prime series, but with the focal length already covered by the 16-35, 24-70 (24-15 in your case) and 50 1.4 (1.
I would have a hard time justifying it.
All things considered, the 50mm focal length is classic for many reasons/situations and will start you down the journey of lens lust - once you get an L prime, you keep finding reasons to get another