I've mained SCH since around 2.2, and going into this expansion was no exception. I like playing other healing jobs too sometimes, and I was, like many people, dubious about the changes to AST, and about how they seemed to making healers too homogeneous and losing their individual identity. However, I continued to play SCH through 5.0 and still had a lot of fun with it. After playing AST for a bit, I actually find the new card system pretty fun.
I do think both of them do need adjustments - 5.05 helped, but didn't completely fix everything. I also think the healer shortage in the game makes it apparent that a lot of people are unhappy and that they need to take some more action when it comes to balancing healers, but I can't say that any of this discouraged me from healing at all, and I still have a lot of fun doing it.