The thing is...in many leagues you need to add to Amari in order to get AB. Seems an overpay for Cooper, but if you want your guy, go get him
No way is Cooper more valuable than Antonio brown in any mature dynasty league, maybe in a league that just started within the last 2-3 years i could see Antonio being worth more.
I offered the same deal for OBJ and Mike Evans and both owners turned it down. I have Cooper as the #3 WR in dynasty. His QB situation is better than Hopkins or Allen Robinson. The problem with Michael Thomas is he is playing with an old QB and the saints don't have a solid backup, he is not a good long term prospect.
I was trading for a guy that I can plug into my starting lineup for the next 6-7 years with no second thoughts. The offensive line is young, the QB is young, and Cooper is a 23 year old WR that has had thousand yard seasons each of his first 2 years. WR's usually start to get better around years 3 and 4, I expect an improvement on his past numbers.
I also watch every steelers game. Antonio disappears when Ben is not in the lineup. Not only is Brown getting older, but Ben is getting older and more injury prone. I expect Brown to have more down games over the next 2-3 seasons because I expect Ben to miss quite a few games during that timespan. Maybe Ben stays healthy this entire year, but I am taking a long term approach.