I've not noticed this at all. I found the 744 and 777 J service pretty much exactly the same. Lackluster catering and indifferent staff.
On AA, however, there is a notable difference between 2-class J (763) and 3-class J (777) on the soft product, namely better FA-to-pax ratio and better catering (bigger portions, better presentation).

On, and by the way, assuming the combined carrier continues to offer a First class on at least some routes, I guess we'll be saying goodbye to "BusinessFirst".