Simon is the embodiment of failure.
I learnt very quickly to not side with Simon, like at all. I can't recall a time when a good thing happened when you went with his idea. If you side with him and Josh in Spare Parts, you only get a limited supply of biocomponents compared to when you side with North, or siding with him and North when deciding on what to do with John leads to the group being chased out of the warehouse, and later if Markus goes pacifist, his own death. Simon doesn't make many calls in the Stratford Tower except 2 if you go pacifist, telling Markus to leave him behind to die and asking Markus to not shoot him. In Freedom March his solution is by far the worst: turning on their heels and running away. And in Cross Paths he tells Markus that North is a lost cause and to leave her to die. These are all his choices that he suggests (from what I can remember), and they all have horrible turnouts.
Simon has good intentions, all he wants is for him and his people to be free, and he's surprisingly reckless with his own life to do so. Despite being careless with his own life, when others are in trouble, he has a hard time taking risks even if it will better his people's life quality. He values the life of his people above all, if an act will cause harm to them, he is hesitant to do it, this prevents him from doing the things he may or may not want to do.
Simon starts out a cautious person, him being in Jericho for 2 years not leaving or making it any better proves that enough (there's literally dismantled corpses piled up on one another in the main room, if they needed to dispose of them all they had to do was dump them off into the ocean, I think most of them were too scared to even go outside). That skittishness did a lot more harm against Jericho than good. His decisions, no matter how good-willed, are what kept Jericho back. His opinion, due to his age, was respected amongst Jericho. While I don't know if he was the leader (idk where that came from tbh) or if Jericho even had a leader but it's clear people respect Simon enough to go along with what he thought was right. Evidently he often isn't. He tries his best with what he's given, dissembling his friends to serve another's or his own needs, but it isn't enough, and Jericho without Markus is destined to rust and fall apart.
Simon is stupidly selfless, I think that held him back from a lot because he couldn't make sacrifices and we see that he is able to with the Cross Paths with North scene but he hates to. If someone shut down naturally, he'd feel less guilty compared to if he made an active decision that would put them in jeopardy. Although I do think his beliefs stem from a place of empathy rather than guilt. He is the one character in the game that isn't an antagonist that, if you mainly listen to, does more harm than good, and that reflects a lot on what Jericho was like before Markus: people doing the best they can but ultimately failing.
Simon is neutral in the way that he doesn't mind violence or care that much about humans, but he has his own opinion outside of pacifism or violence, he wants as many of his people to survive as possible. He understands that it won't gain their freedom but isn't willing to pay the price of their blood. Honestly, I think his indecisiveness on what path to go is from a place of insecurity. I don't think Simon trusts himself at all with big decisions, and he doesn't want blood to be on his hands if (when) his plans fail. So, he grows dependent on Markus to make decisions.
He believes whatever Markus decides will lead them to victory, he is the key to lock that he's been hopelessly picking at for years. If Markus dies in Freedom March, he'll say, “Markus would know what to do” in the meeting during Cross Roads. He really thinks that Markus has the answers to the questions that's he's been banging his head against. I think it's because of that little push in Spare Parts. We see how happy he is when they accomplish their mission, jogging ahead of the group to announce the news, or if they fail to get enough parts, his mouth is agape as he listens to Markus’ speech despite Markus' failure. He has so little hope that even a slight glimmer of light makes him desperately believe it'll glow bright, and he's going to do everything he can to help it glow. Since, nothing he's ever done has even come close to creating that spark because Simon is meant to symbolise the mass, he is a follower pretending to be a leader.
I didn't have anywhere to put this:
Simon learns to take risks over the course of the story, each mission being one of them, but the thing he gets careless with the most is his own life, he can die 13 different ways throughout the game, 10 because of player consequences and 3 sacrifices (technically they're all player consequences, but oh well). Most of them are different variations of each other, but nearly all of them are because Simon was reckless.