make choices that I want based on the kind of character I decided to play.
Playing as an Origin character it just won't be the same thing. You go and change any of the origin and it will be odd (At least for me), Having the option to change their classes (which I doubt) will be even weirder, changing races or even appearance it's not a thing too because they have their iconic looks thrown at you on every loading screen, etc. It just feels fake. So, With all said, I don't think I personally can even try playing without the freedom of creating my own character, even if it will be diminished in the story.
I think that is part of the problem for me. Unless the origin character has unique dialogue for that conversation, then you just get the generic dialogue that a custom gets. Why play as a premade if you still have to define your personality in the same way a custom character has to. I understand your decision to play a custom, my problem more comes down to the fact that origin characters get everything a custom gets and more.
Also small note on the second point, you're right in that we probably won't be able to change class or the like, but DOS2 lets you change the appearance of the origin characters so I imagine they will here too.
