Imagine the Virmire Sacrifice as the Cerberus assassin instead of Kai Leng
Kai Leng was a terrible character from terrible novels. No one wanted him in the games. He could barely handle a Drell with space cancer and couldn’t even kill Anderson and Sanders, but they want us to expect us to believe that Leng is Shepard’s equal? To me I would just have him executed on Omega since Leng DID kill Aria's daughter.
But yes storywise, it's better. Shepard was haunted about not being able to save either Kaidan/Ashley. TIM would use the Virmire casualty as Plan B should Shepard turn against his interests.