Then I'll hammer in on the really important bits:
Adam, right off the start, is augmented to the point where it's obvious he's extensively machine. In other words: your change in appearance has diminishing returns.
I don't think you're on firm footing to talk about lazy routes, considering you're defending a feature where "reactivity" is maybe 3-4 npc's making half-joke response about dragon tattoos, at the expense of a character creator.
I am sorry did I not make myself clear enough? The idea that Bioware should abandon the character creator in support of pre-defined appearanced is a farce on my part to demonstrate how stupid the pre-defined backgrounds are, the idea you would take freedom away from the player to define their own character just so the player can watch their character spout exposition about their drunken aunt is just as stupid (if not even more stupid) as taking away the player's ability to design their character's appearance in order for NPCs to comment on their appearance.
But that being said even though Jade Empire did not have much reactivity when it comes to appearance it does not mean that there can't be more reactivity based on a character's appearance, take for instance Vampire, the Masquerade: Bloodlines, you had 7 playable clans each with their own visual distinctions, while most of the playable clans looked human enough to be able to interact with normal humans and show their face in public the Nosferatu looked like hideous monsters, not only did their visual appearance effect how other characters reacted to them it also had a profound effect on the gameplay, you could not show your face in the street or talk to normal humans otherwise you would have Vampire hunters come after you and you had to travel via the sewer in order to avoid detection.
Visual appearance can have as big or as little effect as you want it to, you seem to be viewing things in a very narrow spectrum but you need to open your mind to the bigger picture.
It looks like you're going for the analogy, excluding one giant hole in this point.
Let's go back to the thought experiments using your analogy. We make 2 characters, mostly the same in every respect, except one has black hair and the other has brown hair. They make all the same choices/dialogue options and everything plays out the same.
Now, we make 2 characters, exact same appearance, but with radically different backgrounds. One of them, a Femshep, lost her father when she was very little to an assassin, but still somehow finds herself romancing Thane. The other, has had a completely normal backstory, but both are forced to have the exact same responses, despite radically different circumstances.
If that's the "price you're paying" for role-playing freedom, it doesn't sound like you're getting a great deal. That's where your arguments fall apart. The analogy only works if you treat those two quantities as maintaining equal importance in terms of believable interactions, hence why I keep pointing out to you how much more difficult it would be to live your life without referencing 20+ years of experience than it would be to avoid comment on people's appearance. If the game never draws attention to the fact that you made a character with black vs. brown hair, while that may show a "lack of reactivity", it's no worse a concept than what we could achieve in day to day life. Now try that with your character concept and let's see how far that goes.
Thing is I don't get anything from a pre-defined background so the cost for role-playing freedom I pay is nothing, on the other hand not only to I get nothing from being able to have my character recite lines about a backstory that means nothing to me and nothing within the context of the game but I also lose that roleplaying freedom to define my own character so it is a lose lose.
I honestly don't recall Shepard's background having a huge influence on the Thane romance (pretty sure it did not) but even if it did it must have been so inconsequential that it was not worth remembering which brings up the point why bother with it in the first place?
Maybe you'll come back and say "but look how ridiculous I made that character!" and that's where I'd again point out that this is easily circumvented by not making characters that you concede are utterly ridiculous. I can't think of many character concepts where no one says a single thing about his past, ever. None that I'd be interested in playing, anyway.
I guess that is the difference between me and you then, I prefer characters who act and are defined by their actions and don't look back, you seem to prefer character who bore everyone with long monologues about the glory days or some sappy sob story from their past and does not get anything done.
No, you're falling into the same trap, just with a different backstory now. If that's my character's backstory, I should be able to tell people "hey, I can't remember my past, what the hell happened?" or express some interest/effort in understanding what happened with my background. Which coincidentally Planescape: Torment pulls off pretty well.
Yes there are always exceptions to the rule and Planescape: Torment is one game where a protagonist with a defined backstory works in the context of a video game, there are several reasons for this.
1. The character has amnesia, this puts both the player and the character on the same page when it comes to knowing about the character's past, both are in the same frame of mind and both learn the information as it is revealed to them, it is a journey of discovery that is shared by both the character and the player.
2. the backstory actually has relevance to the plot, unraveling the mystery of this Nameless One character and learning of his past is what the plot is all about.
3. the game does not imply that the character should feel a certain way about events and characters revealed in the game, it is always up to the player how the Nameless One feels about the events that have transpired and what type of person the current incarnation of the Nameless One is. Whether you feel bad about what previous incarnations did or whether you don't care and feel your incarnation would do the same thing in the same situation, it is completely up to the player.
Maybe your character has unresolved parent issues, just like most other Bioware characters? Maybe it's a way to develop a closer relationship with your companions/romance options since, you know, people tend to talk about themselves with people they're close to. Maybe, just maybe, it makes a character feel more alive than simply functioning as a doll, oblivious to his environment. Expressing different ideas and emotions through dialogue and actions tends to be kinda important for role-playing, believe it or not. I appreciate that you're trying to brush this under the rug with "Pfft, your life story is boring!". But that's what's odd about this: a character backstory doesn't have to be boring. But with your approach to game design, it's guaranteed to be irrelevant.
Just because a character does not focus on the past does not mean they are oblivious to their environment, the exact obvious, by shifting focus away from inconsequential events in the character's past it allows the developers to focus on making events and characters in their present more relevant, just because they don't reference events in their past does not mean they can't express ideas, thoughts and opinions, in fact by not forcing a background on the character it allows the player more freedom to define what those ideas, thoughts and opinions mean to their character thus giving them more relevance to the player.