Sure, I guess I see that -- kinda felt like more generalizations because you were asking questions not about how those examples worked but about something that just involved one of the bits from the examples. Also, the idea of getting a secret from a roll on a table wasn't part of my suggestions. I guess I missed this.
Okay, yes, characters don't exist. But this is rather a banal point when we're talking about pretending to be elves -- hopefully we all understand they don't actually exist and instead are talking about the ways we pretend they do. And here, in this pretend land, I'm staking the claim that there's a difference between straight authorship -- where you 100% define and control your character -- and play where character is risked -- you do not always define and/or control your character. And further, that there's a distinction between expression and definition/control -- you can express something you don't have authority to control or define (this is one of the things an actor does).
So, when we get down to talking about being pretend elves, that it's make believe is given. I'm looking at how we do the pretend part.
But for a lot of us, a randomly decided reaction of what my character would think or do is not "discovering" anything other then potentially a new entry on a list. It's kind of like when you're playing a video game RPG and the cut scene comes up. It can be entertaining, annoying, exciting or boring. Sometimes the cut scene will be affected by what my PC has done, sometimes everything up to that point has no impact whatsoever. I don't know enough details about the games you've referred to, but it sounds more like the latter. In either case, having a decision of who my PC is is not why I play D&D.
I don't usually think through "how would my character react" to much of anything. I think of their background, where they came from, what happened before the campaign started, why they're risking life and limb to do stupid things like trying to stop the BBEG. Frequently that background and who the PC is will just be a starting point, the personality gets fleshed out through play.
You may not call that growth of a PC from an outline to a more filled-in person discovery, but it is one of the more rewarding parts of RP for me. Going back to Mr B, my current vengeance paladin PC, part of his background before the campaign is that he lost is (pregnant) wife and young daughter. He feels guilt because he was not there to protect them, anger because while the people that killed them were hunted down and killed - by someone else. He never had a chance to personally extract vengeance.
So let's say at some point he finds someone that has his daughter's necklace. The only way the NPC could have gotten it would have been to take it - this was someone responsible for his families death. But ... as far as Mr B can tell, the NPC has turned over a new leaf. He doesn't know who Mr B is, but truly seems remorseful and is trying to atone for past sins.
How does this get resolved? By the roll of a dice that references some chart? That to me wouldn't be "discovery". It would just be some random s**t from a chart that doesn't take into account the somewhat complex situation. It would have no meaning, no impact. On the other hand, since I've been playing Mr B, I might just react without even thinking it through, it would not be a conscious decision. I might ponder it, try to put myself in his shoes to decide how to react.
Is that "discovery"? Maybe not. But a random reaction wouldn't feel like much of anything other than a random reaction to me. Deciding what my PC would do given his background and previous actions? It's exercising my empathy muscles and creativity. It can even be somewhat revelatory. It's doing more for me than a random reaction ever could.
On the other hand if random works for you, great. I don't see how, but I'm not you. Just like you don't know what goes through the minds of other people when they're role playing their character. If "the character takes a direction I didn't expect" is the best way I can describe it, it's not up to you to dismiss it as meaningless.