The difference between Original Ada and Remake Ada is that Original Ada portrayed as someone working for a secret, unnamed Organization with unknown goals. Remake Ada portrayed as "just a mercenary" (thereās no mention of Organization).
They both betray Wesker at the end of RE4, but for different reasons.
Original Ada was following the Organization's orders. She didn't send Albert the Dominant Plaga because sent it to superiors instead, leaving Wesker with a regular Plaga that was useless to him (so he takes this from Krauser's dead body). Thatās what she talks about in Fifth Report, confirming that was "their plan" from the start.
Remake Ada did it because of her own moral compass. The whole game sheās questioning herself morality keeps coming up because of how much Raccoon City affected her. She hesitates over whether to send Albert the Amber, and when she realizes it would lead to millions of innocent deaths, she refuses. She takes a huge risk and turns the helicopter away from Albert (lucky for her, Albert decides to let her go).
I'm not saying one version of Ada is better. I love both of them. But they clearly had different motivations.
