gonna try to condense my thoughts in a way that does not turn into a mini essay but fallout 4 is a story about little people making big changes through combined effort and knowing their worth. regular ass guy/woman comes out of a vault after 200 yrs and retrospectively changes the commonwealth for the better or for the worse in a (all things considered) very short amount of time w/ the help of everyone around them.
im going to specifically compare nick valentine and paladin danse, not bc danse is my favorite but rather bc thematically he's a parallel to nick and vice versa. nick is a synth; he is outwardly a synth and very easily identifiable as a synth. by this metric alone he'd never be a brotherhood soldier, unlike danse, who is indistinguishable from someone who's naturally born human but despite this, as we know he is also a synth.
the game hammers this in but the point of it is danse structures his self worth, his philosophy, and his very right to live around being born a human and the idea of being a synth is a violation of humanity as a whole. important to note, danse also does this as an extension of the ideology of the brotherhood itself. the brotherhood, as does danse, believe they are the only hope for the people of the commonwealth and they alone are what it would take to infiltrate and dismantle the institute.
nick does not structure his self worth this way, and he does not structure the worth of synths in this way either--or anyone else for this matter. nick knows he is a synth, he has always been a synth and he is VISIBLY a synth, but his philosophy is that isn't what makes you human and being a human, even being a soldier, isn't the only way you can make a change. if it wasn't for nick helping the sole survivor, knowing his worth and not letting it be defined by the fact that he'll never fit the "big picture", no one would have ever found the institute because there would have been no one willing to look for shaun at a time when diamond city had several other things going on. the only other person in diamond city would have been piper, and she is too distracted and too unreliable (no hate to piper) to rlly sit down with what tss has going on, and if she could she doesnt even rlly have the information/skills they need. that being said, piper is also useful in her own way
the only other contender MAY have been the brotherhood, but the brotherhood would never have found out abt the relay w/o tss. and tss would have never found out abt the relay if it wasnt for nick helping them track down kellog, which no one else was going to do or even COULD do. tss needed someone who would get into the nitty gritty of what happened, someone who knew the commonwealth and the people in it. that person wasn't a brotherhood soldier, or even a human, it was nick--who spent all of his time tracking down missing people because he genuinely wanted to make a change in people's lives in ways no one else had the time and/or heart for.
i'd also like to add that this doesnt mean the brotherhood or danse's relationship w/ tss is redundant, or anyone else for that matter, because i do think realistically the brotherhood is going to be the only one w the firepower to rlly take on the institute. they serve their own purpose, but if it wasnt for tss and nick they would have never gotten to that point
i failed at making this not a mini essay goodbye everyone