There is a old saying that a tiger cannot change its stripes. We all knew from day one that EJ was a snkae. Yes he is good looking and charming and well dressed and confident etc but in the end he is a snake. He had an agenda from day one—Sami. I think you can say that he is OCD ( obsessive compulsive disorder). I would also bet that he is not use to losing, not to Lucas and Not to Rafe and esecially could not forgive lying and sneaking ( only HE can do that). THe best revenge is to make SAmi suffer and at the same time get close to him.
Perhap at the start the writers hadn’t decided that HE would be the mastermind, but in the end HE is evil. If he truly loved Sydney, he would not thrown her out when he found out the truth. He has not concern for Sydney, she is just his property. He kept talking about mourning a child that was not his, that he thought that he never knew his daughter. Nothing kept him from knowing Grace he wanted no part of her because he didn’t think he was connected to her. He raised Sydney from birth and threw her away like yesterday’s garbage!!!
There is no redeeming EJ in my eyes, starting with the "rape" and ending with his attitude toward Sydney. He might be a hunk but he is bad news!!!