Hi Andriyko,
great to "see" you again
I have a round trip First class ticket, so I am surprised on this fee as I was told it was introduced on Friday 2 weeks ago. I think on March 3rd or 4th.
Yes, it is cheaper to buy the domestic leg separately but I prefer the whole trip as one ticket and also usually the baggage allowance in this case applies throughout the entire trip. If I have a separate AA ticket then it is a bottle neck in terms of luggage just in the middle of the trip.