Samara: I don't have a problem with her character (I actually like it) but rather just a single aspect of her character, the Justicar Code. While a character who serves as some sort of monk adhering to an ancient doctrine is intriguing, Samara suffers as a character from it because some of the tenets come off as completely arbitrary or as a handwave to move the plot along. Also, I found it weird that Samara and the Code were often associated with Paragons when the first time Samara appears she is performing an arguably Renegade action (you think Paragon Shep would turn the mercenaries into the authorities).
I just want to say that Paragon/Blue at the time of ME2 for Shepard, isn't the same as Paragon/Blue for another character.
Blue often really just means.. any code/Code/Order/Law. It means a restraint of freedom, for the cause of something beyond yourself.
So to Samara, it doesn't matter if she internally disagrees with killing that merc. She already prioritized the Code over all things - until finally challenged by the possible death of her last daughter. At that point, she partially relents, and stands at crossroads. Unable to kill her daughter, but unable to give up the Code that she kept for 100s of years.
Paragon Shepard is rather different. I consider him 'core' Renegade. He's not looking to keep a moral code. He instead has an obligation to whatever he's more allied with (first Alliance, then Cerberus, then Alliance again). *They* have power over him, not their ideals.
But we can go Paragon, in order to resist that dominance over Shepard's values, and try to 'find other ways'. Whenever we go Paragon, we're LOOKING for a 'code', a way to help others beyond our central duty or self-service.
Just so happens that eventually this means that we find our Code. As a Reaper Controller.