I had the same experience as you in one respect: I sent in two compliment letters on the same day, one related to cabin crew and the other to the concierge group. The “replies” I received were bland and identical, and didn’t reference the specific individuals I had mentioned.

AC made a modest effort to acknowledge these letters in the past. They might still have been using a template, but the AC people replying at least modified the responses somewhat to reflect what I said and to reference the people I mentioned.