I, too, surprised myself by recently purchasing a 6D (I, not II -- why increase weight and dark noise?) on both lens-selection/lock-in and quickness concerns. I was surprised to find that I loved being able to leave the camera switched on all day in the mountains and draw/shoot/stow in seconds, with 1000+ images on one battery. Barring substantial advancements in sensor/display power consumption, no mirrorless camera can match that property. Furthermore, it is an instrument I can handle/adjust quickly and reliably with gloves on in harsh conditions. For a week at temperatures between -20 and -30 C, the 6D (and iPhones kept warm) operated normally while friends with mirrorless cameras suffered shutdowns.
The three things, from my perspective, that Canon really lacks are 0.5-1 stops of dynamic range in the sensor (SNRs are competitive across all brands, an underappreciated fact), silent electronic shutter, and Sony's incredible array of on-plane focus sensors and focus algorithms (Canon's DPAF may actually compete, if turned loose/optimized further). Sony's eye-detection AF must be a game-changer for portrait photographers.