I've been having the same problem, and am on a Mid-2011 iMac too. Having just spent 2hrs trying to get InDesign CC to load properly, I think I'm back up & running...
I found a reference for a conflict between having the Menu Bar automatically hide/show... I didn't have this option checked, but I did have hide/show Dock - so I've turned it off, and have also reset InDesign preferences using the keyboard command here. Try unchecking either/both of those then launch InDesign... it may take a while again as it recreates its fresh settings... then quit from the File menu, then load again as normal.
Hopefully that restores your launch speed. It's worked for me. My next step was to try other suggestions posted here, and then a clean OS install but I seem to have been spared that!