The only problem with Amazo as a JL villain BY HIMSELF is that he has NO character. He's simply a kick-ass android. He would have to be used with another villain, and most likely a big name. It's hard for moviegoers to get excited about a supposed game-changing blockbuster with a big bad who's not a big-name or that deep of a character. You could point to Avengers to try and dispute my claim, but the unfortunate truth is the avengers had established a fan base after multiple successful stories. Bottom-line, Amazo is too shallow of a villain to carry a JL film, especially one which has to battle with Avengers. However, using Amazo in conjuction with Lex (and made by Morrow, a Lexcorp scientist of course) in a MOS sequel would be a great way to introduce the real threat of earthly villains and also force our main heroes to use their intellect, yes intelligence in a comic movie I know, to defeat the villain and will also set the stage for teamwork which can blossom even more in a JL film. This would make it so that the whole "let's fight, and then become chums" cliche in every teamup film, and instead they can focus on character development and other things which could make JL standout even more from its competition.