I have exactly the same issue with the same printer. Had it for over one year and used the original cartridges and genuine Canon replacement ones. The colors from day one have been consistently very poor. No pop at all and like you had mentioned, excessive reds and generally washed out colors.
I had heard from others that this printer is known for poor colors and is much better as a blank and white printer.
I have owned a Canon S9000 that i purchased new many years ago...excellent results. Years later I bought an Epson Stylus Photo 1280 that I bought on clear out for $250, excellent results. This Canon Pixma Pro 100 is IMO in a completely different league, absolute inferior results and it is very difficult for me to imagine that my printer is behaving normally. It is possible that Canon went very cheap on the internals of this printer to maximize profits.
I WILL take this printer back to my LCS and ask them to try to generate good photographic results using it. I doubt that it is possible. If they can't get good results out of it I will definitely be asking for deep discounts on a printer(s) that can actually print acceptable photos.
I don't think that your results and experiences with this printer are unique. I think that it most likely is an inferior product. If I find out differently I will post again.
Best of luck.