I love how at times, for just brief moments, they show that Ra's has a softer side and is still human (sort of). Like when he says a prayer for the people he kills, when he spoke to Felicity about his old wife and kids and then told her to make the most of her last moments with Oliver and how he hesitated to kill Damien Darhk. These moments are far and few between his general ruthless self and make no mistake, despite these moments, he is ruthless. Oliver almost killed Nyssa, his daughter, under his order. He has killed lots of people (and his first kill came at age 11), he killed Thea and had the entire Starling Police Department after Oliver just to get him to join the LOA, the way he has taken Oliver from his friends and family and is now stripping Oliver of his soul and everything that made him who he was in front of their very eyes (for a lot of people, it would be preferable for their loved one to die rather than become the unrecognisable monster that Oliver is becoming) and now he plans to exterminate Starling City.
The Ra's Al Ghul picture that the Arrow writers are painting is one of a man who is back and white in how he is uncompromising in his judgements, but there are also grey areas in regards to him. In his own mind he clearly believes he is doing the right thing and that his way is the way the world should be ran. After his experience with Darhk, he sees reluctance and hesitation to kill as a mistake that can have serious consequences and as a result, you cannot leave anything to chance and you have to eliminate any potential threats and leave no bad deed unpunished. He believes the only way the world can be a good place (or a place that is run how he sees fit) is if it is ruled with an iron fist and for no prisoners to be taken, for the League to achieve its goals by any means necessary, by hook or by crook. Emotions such as love and kindness are weaknesses in his eyes that prevent you from doing what must be done and hinder you from reaching your true potential as a warrior. I suppose he summed his philosophy up nicely when he said that he "replaces evil with death". All of this, is to achieve what is right and what is justice in his mind. From his point of view, he is the good guy and the judge, jury and executioner of the world and his vision is what is best for everyone. He has had innocent people killed but in his eyes it is to make thing better for others and to stop more deaths in the future. He would kill his own daughter and have her replaced by someone more suitable for the task at hand, if it meant that the world would be a better place so it is not as if he has double standards and only applies his severe rules to everyone else and keeps people that he may have grown fond of alive because it suits him. The sacrifices that he thinks it is necessary for other people to make, he is willing to make himself if needed. I love how Matt Nable has portrayed him. The two live action adaptions of Ra's Al Ghul have been fantastic.