Some of the complaint seems to be of nature that since cats are animals and dogs are animals, therefore cats are dogs

(a) The same AA flights are available to book
(b) There are now also codeshare options
(c)Prices for recently made bookings are more expensive than before

(a) plus (b) does not imply (c)

It would read that other than being grounds to complain, that you have grounds to be content since there is now additional options to choose from with the US flights as far as being able to credit to AA rather than either paying for the more expensive AA flights or just booking elsewhere