To make Jeremy an MC, it's not enough to just expand his background, you have to rebuild him from the ground up. Right now his exposure is such that he's not a "bruised nerd to wannabe player," he's just a "stupid BBC wannabe player. We never see the other side or for him to do anything clever. He couldn't even come up with a convincing lie for Louise, who believes him simply because she is naive and desperate. The only way we know he was a nerd is through the dialogues. So it's not enough to expand his backstory and show his other side through choices or rework him like Stan, because that would be unconvincing and wouldn't get the dynamics we need. What's needed here is a completely different character.
Not necessarily, in order to expand his character Eva would merely have to maintain the core character traits she established, and expand him in a way that was consitent with that. Hell his whole current persona in the game could be one possible path for him, and his whole arc could focus on the whole "nerd wants to become a better version of himself", with a thematic focus on him becoming a more authentic version of himself, or what others want him to be( an arc kind of similar to Lena's). Building him from the ground up isn't really necessary.
Cobra Kai literally does this with Johnny Lawrence, who was an incredibly basic character in KK1, but instead of rebuilding him, they just expanded on what was already there. Johnny's still an asshole, but he also has more endearing aspects to him, and reasons for who he is.
nontheless the person was just saying, that if Eva made Jeremy the MC, he would have gotten a lot more development, and be strucuturally different than he currently is. They don't really care if he's the same or different, but rather are pointing out, that whether ppl dislike him or not now is irrelevant as he would be much better written by Eva as an MC.
