For the last part my wild uneducated guess is that you (we) had to restart so that DPP launches automatically when you connect the camera to Mac. Perhaps some drivers, daemons etc.
EDIT: nevertheless I agree fully that the whole Canon software user experience is bad.
Yeah, Canon makes some killer HW, but their software is a bit stone-age.
Side note for happy happy thoughts: Your photos have really jumped with color since the upgrade to the new unit. They have added a greater level of a bunch of things which I will add elsewhere for you but overall the new camera is making a difference with your photos, awesome work
Thanks very much!
BTW, here are my DPP observations...
It's interesting but after finally getting DPP installed last night, I spent some time comparing the RAW processing between DPP and Aperture. Interestingly, with both apps at defaults (no adjustments in Aperture and "faithful" in DPP) the images in Aperture looked better... they were a bit more contrasty and saturated with a bit more visible in the shadows than DPP. Now to be fair, these differences were really only visible by pixel peeping so it wasn't that significant.
Of course, both apps could tweak the dull RAW images into beautiful images. I found DPP's Unsharp mask sharpness similar to Aperture's Edge Sharpness and a "3" (Standard) on DPP was about equivalent to the default settings of Apertures Edge Sharpness setting. However, for low noise (low ISO) images, I prefer the "Sharpen" adjustment in Aperture which produces less contrast artifacts to my eye. There is no equivalent to this in DPP. Their other sharpening choice is a mushy mess.
I also could not see any benefits to the new lens correction... but I must not be doing it right. Need to play with that more.