Say what you want about Dez, the man bled blue and silver. Sure, he was never a great route runner and age caught up with him as well as losing focus, but before that he was a serious threat. If I was offered the choice of Dez in his prime and Amari in his prime, I'd take Amari, but Dez was no slouch. Part of his problem was the system he was in. Linehan didn't know how to use him and he didn't have a WR coach that could get through to him.
There is no need to build one up by bashing the other. I hope that by the end of his career, Amari will bleed blue and silver like other great Cowboy WR's. He seems to love it here already.