I'd say Blissey is the most curious one that wasn't retconned, due to it seeming like a sure candidate that fit well with the aspects of the type (that don't involve being mischievous, of course).
Since Blissey symbolizes mother's love / the unwavering kindness of nurses, I think that it seems fitting for Blissey not to be retconned. It shows that even if you are normal, if you have pure love things would turn magical.