So why not Cora?

Dude what?
If you do something wrong that does not undo everything you did in you life. The teaching is valid but the teacher is a hypocrite. That does not mean what they are teaching is not valid it just mean they can't live by their own standard. As Draco said if all those books and teachings made her half the fighter she is then it's worth keeping.

I agree. I would have liked it if Alec had lived and remained Pathfinder while we work for him, carry out his orders, and have to live in his shadow. It would have made the family story more personal. The chosen one "Call the hero by a title" nonsense is tired. I'd rather had been Alec's screw up kid who turned to a life of crime on Kadara or be stuck trying to live up to his N7 rep while helping out on the Nexus. Something different and interesting. This is why I loved playing the Sith Inquisitor story in swtor, and hated it when he became "The Outlander" 

they made her good at being a good little soldier ant...nothing else

dude...LISTEN TO HER she says it herself she is "GLAD Alec picked you and not her" because "she is not cut for it" because "she is not a trailblazer and always looking for the mentor to follow". You keep thinking that we can see her evolving and shit but there is no concrete evidence of it, you just want to see it happen and it is not.

At least for a while. The premise is, you set out as a family. It would have been good to get to know them, so there's at least some emotional connection before losing them. And no, the memories don't count towards getting to know them. You lost a cardboard that is filled as you recover bits an pieces. But devs don't have the guts to play that out these days. The most glaring example being FO4 where many people don't give half a shit over their lost son, although he's set out to be the main plot line.

dude she was being groomed to be a leader and yet by the time it was her time she just could not step up even in her own words. Just leave Cora where she is before she becomes another Ashley

some people never rise to it because they lack the mentality and aptitude for it. Why exactly do you want this so badly

I think they could have solved the obvious dilemma pretty easily, by not making Cora second in command. But that's not how videogamy stories work today. It always has to be the kid with no name rising up to be the hero of the hour. Personally I think it's a mild insutlt to the player's intelligence, since many would have been comfortable with playing out their predestined role. Videogame stories always follow one of the oldest cliches in storytelling. Personally I'd wish for writers to grow some guts and to challenge the player. Rise up to the role the game has in store for you. Don't resort to mental acrobatics to make John or Jane Doe the hero.

I would have liked for Alec to stick around for some time. That would have killed to birds with one stone. One, getting to know your father outside the memory collections and the other being prepared to slip into the role. Nothing wrong with that. It's just that all devs these days are afraid to take risks. To lose someone who's more into casual and into the basic of basic hero tales.

Cora is not made Pathfinder because it is now impossible to remove SAM from Ryder without killing Ryder. Alec transferred control of SAM to Scott/Sara. If they were to transfer that control to Cora, Ryder would be committing suicide.

And Cora already has a SAM implant. At least I would assume all the Pathfinder team did.

where do you see it? When she wallows in her feelings after Sarissa reveals herself for what she is and needing Ryder to kick her out of it? Or when she admits she is happy NOT being the pathfinder? The best she did was parrot Sarissa's manual to Sarissa's second in command to calm her down. Even if she could take charge in a punch she would rather follow and she says so herself. As opposed to Avi who even not liking the role and having lost his mentor immediately stepped up and started being the pathfinder, leading people and organizing them and even trying to find clues (successfully) about the Turian ark. He did not let someone else take the lead.

No it doesn't have to be that way but it does make the job a lot easier.  If we need an AI to help us explore in the future then there isn't much hope for this endeavor.

explorer ≠ pathfinder