Ive seen so many people saying Leo was a wuss because he didnt wanted to kill the boss's but I personaly think it was a kind of philosophic message from the producers to tell us that killing others was not needed. What do you think?

I kind of think he is a wuss,but after his friend got shot by Viola, I think that triggered a sense of emotional anger, forcing him to not care whether(SP?) or not he kills Viola

I wouldn't call him a wuss, mainly because he is a kid that managed to learn how to pilot an orbital frame in minutes and defeated all Barham unmanned robots and 4 elite soldiers who where using orbital frames. He even fought with Anubis, though he retreated once he realized it wasn't possible to defeat it with Jehuty at that time.
Maybe he's not a hero, but he did things that ordinary people wouldn't have.

There's nothing wussy about not wanting to kill people. By not killing them, he risked having to fight them again and again. He stuck to his beliefs even in combat that could cost him and Celvice their lives. Thats anti-wussy; it's bravery to a Vash-like degree.

He's not a wuss, but someone who was thrown into a situation he did not want to be in. Killing people IS stupid and it is a good thing Hideo Kojima and his team tried to show this. This game is so good only because of Leo....his emotions are the good part of the story. He doesn't want to kill but protect people and that's good. Not like Kratos that only wants to kill.....So no, he isn't a wuss, nut neither is he a hero. He's a human. A normal human. We're not all killing machine's and it certainly wouldn't be good if we were