Every single fight in the second tier of this expansion requires heavy use of healing ogcd's. If you are using your GCD's to heal the tanks then ofcourse you're not going to need your ogcd's as much because you are overhealing the content... you can and should handle about 90% of single target healing requirements with healing ogcd's and not a regen or aspected benefic.
But just to give you some solid examples, proto-carbuncle had some heavy to heal single target mechanics, so did p8s phase 1 and phase 2. so did p7s. But Yeah, if you're stopping dps to single target heal GCD then you are invalidating the use-cases for your abilities. GCD heals are for when you have nothing else left to press.