You said you didn't want to determine things randomly because you wanted an 'interesting package'.
I want to
put together an interesting package. It's the "putting together" I wanted to emphasize, the "leveraging" of options, not the interesting-ness. Dice--cards, computer programs, whatever--randomly selecting options from a palette removes me as an
author of a character. In my mind, which need not apply to anyone but me, it turns me into merely an observer. I note the existence of a particular set, and find that set assigned to me; my participation is neither required nor pertinent. That's how it makes me feel, because I play no part whatsoever in
making it. Much as, for example, I would feel no special attachment to a vehicle randomly assigned to me; it was made by another, without my input, critique, or even awareness. In the course of time, the brute nature of
using the vehicle will give me a certain sense of possession, because I would be using it, because it would be a "personal" space (in that odd way that cars, so clearly public-facing, are "personal"), sure. But it would never be as close or as dear to me as a car I carefully selected, modified, and detailed myself (or worked with others to do so, since I lack...pretty much all of the skills necessary to modify a vehicle, mechanically or aesthetically).
Same goes for a character randomly generated. It was generated without my input in even the slightest sense. Its existence (in as much as TTRPG characters "exist") is wholly independent of anything
me. It lacks even the sentiment of a gift, vicariously "mine" by being chosen by another with my preferences in mind, and being a physical representation of the relationship between us. It is merely a combinatoric event, which by happenstance was assigned to me; for me, it is barely more evocative than a social security number or the particular swirls of my fingerprints.
I think that can be done with randomization. It sounds like what you are saying is that you don't like randomization in character creation because you have a specific concept in mind that you want to play. Sure, that is exactly what randomization denies.
Which is more or less what my previous statement is trying to clarify: the thing I want to do,
putting together an interesting character, rather than
happening upon one (or discovering it, if you prefer), is incompatible with the kind of "hard" randomization you described. I'd argue that it's also incompatible with "soft" randomization (e.g. the "roll-and-assign" thing), and yet that method also seems to oppose the kind of thing you (sometimes) want. It undermines me, because it removes agency; it undermines you, when you seek such, because it removes the "surprise" factor, making certain results (a 15+ as the character's prime stat, frex) effectively guaranteed.
To say that the characters aren't interesting, or in your new post, potentially not effective is not true. There are ways to mitigate that. I like cards because the sum is always the same (or similar).
But by doing so, you create precisely the kind of thing that, at least in general, fans of "strict" rolling rail against: cookie-cutters. Having a high stat
mandates having a low stat, and vice versa...you just aren't getting the choice of which one it is. Perhaps that doesn't bother you, but it's still departing from genuine, thorough randomness (presumably in the name of "fairness" or "balance"). Any form of mitigating the over- or under-effectiveness of randomly generated characters by its nature must make some part of the character foreknown (non-random, deterministic). To mitigate all dramatic deviation from the mean, you have to constrain the range...which leads, in the card case, to all characters who have at least X for a stat ending up with at most something like 25-X (or whatever the chosen value for 'mirroring' is) for another stat. (In other cases it leads to other things, like a narrow region for acceptable stat values e.g. "only 8-16" or the like.) These things prevent outliers by making true outliers impossible--a strict reduction in randomness, aka characters that are more similar to one another.
If you don't remove the true random variation, you leave open the very real possibility of
at least one person being abnormally above or below the party average--and for a 5-person party, binomially speaking, those odds are quite good. You may only have a 5% chance of being 2 standard deviations above or below average individually...but having at least 1 person out of 5 being in that region is just over 22.6%. If, instead, we look at 1 SD above or below, the odds of at least one person being outside that range is 86.5%--and better than 50% odds that at least 2 people will be. That absolutely can lead to observable differences in success between players, especially if one person is 1 SD below and the other is 1 SD above.
So...no, I think you're wrong. If the randomness is genuinely "hard," genuinely open to
all possibilities regardless of prior or subsequent outcomes, then it is an unavoidable fact that
some results can be noticeably better/worse than the rest. I dislike being in either position, and don't particularly relish the thought of even being in the "average" group while somebody else languishes at the bottom of the heap or rises above the rest (happily or unhappily, doesn't matter). All such situations strike me as unfair, and the only way to "mitigate" it is to abandon the commitment to hard randomness. Perhaps a partial commitment is sufficient to satisfy you, but for me, personally, it appears little better than lip service to randomness while still denying me authorship of my character, and thus sort of
worse than true randomness, which at least consistently pursues a goal, even if it's a goal I have no interest in.
It's not for everyone but that doesn't mean it is wrong.
Perhaps my repeated emphasis on my emotional reactions ("I hate..."), my personal abilities ("If I have a specific story..."), and effects being applied to me ("deny me that agency...") was insufficient to make it clear that I was speaking about myself. Your "people like different things! It's not objectively wrong!" rebuttal thus strikes me as clouding the issue.
It is an objective fact that, by surrendering control of these details to a (pseudo)random number generator, you are surrendering your agency with regard to what the character will be. It is no longer your
choice, it is dictated to you by something else (dice, cards, computer program, whatever). That some people may enjoy that state, even greatly, has nothing to do with whether or not it happens. It is at best a non-sequitur, and at worst an attempt to paint me as insulting other game styles, when I am only saying that that randomness removes agency. I made no other objective claims than that. All other claims were not only subjective, but purely centered on myself.