Actual Pen and Paper Role playing games don't met your definition of being a role playing game. Simulating countries and mecenary bands or guilds with diverse values and points of view would involve reps, could have temporary alliances, which is what seems to be missing from RPGs. Designers never thing in arcs where you temporarily ally with a group while it is convient. Intended arcs tend to be all or nothing, pick one side and be done.
errrr, what? That statement makes me kinda sad for your P&P RPG experience :/
Think more Reign and the like. They just provide stats and mechanics for running your own factions, and having groups interact. By providing mechanics, you get concrete ways of manipulating things, and don't have to rely on DM rulings and fiat to move on. Those RPGs didn't met his requirement of not putting numbers to things.
It's not about hiding the information, but the METERS.
People running from you IS information.
Soldiers attacking you on sight IS information.
Thieve's guild looking to recruit you IS information.
Big glowing bars showing EXACTLY your current relation level with all the thresholds and bonus is information too, but it is retarded
Those examples show the consequences, but not opportunities to change things. They're also rare pieces of information. I imagine a bar as an abstraction to all the tiny bits of dialogue and reactions that games couldn't possibly include. Soldiers attacking you on sight isn't helpful information - that's sadly the default in games. And when it happens, does the player even recognise that an alternative existed to make peace or otherwise get past without resorting to combat? I see a bar and I think maybe there is. I think maybe my actions will matter in determining their reaction. None of them actually tell a player their actions have mattered. People run away? That's some nice scripting. Thieve's guild is looking to recruit me, I guess that's a quest line offered to everyone.
Not including feedback makes the game with a single play-through that has consequences the same as a well scripted yet railroaded game. Because frankly, past games have taught a lesson to be cynical about how they approach these things. I'd like to know what matters, because frequently I can steal and kill without consequence. Or the opposite extreme which is also useless, of having it ruin the game and therefore being relegated to a single attempt, and then reloading.
I play D&D and I know all the numbers. How much damage a sword does, and how much health a first level fighter will have. Why does combat get a pass here? Aren't non-combat mechanics the freaking goal? Imagine you have a game where you don't know how much damage you're doing with each weapon, and how much health enemies have. (One comes to mind actually, Necropolis suffered from this) The way I reacted? I didn't care which weapon I used - because they all seemed the same (laughably in Necropolis's case they all had slight situation buffs, but the descriptions were useless and you'd have to devote time to real scientific experiment to notice the difference.)
Without feedback the entire system didn't matter, and was a waste of the developer's time. Also realise that combat decisions happen quickly so those experiments and feedback is easy, whereas the results of dialogue in making people hostile not only happens once, and often irreversibly, but also builds from many individual choices and the payoff is so incredibly displaced that the average player simply hasn't got a chance to notice that those dialogue choices actually mattered.
edit: Look I don't think it needs to be bars. Notice the parallels between this and diplomacy in 4X games. The various games in CIV have suffered from this. It's not enough to support diplomacy, or to have an AI that makes decisions based on player action - they need to tell the player WHY Genghis is attacking. Sure, the reason might just be that he's Genghis, but if it's because I settled too close, or have the wrong religion, let me know. I might be able to do something about it.
EU4 gets this right. Because I know my relations with other countries and the fixed modifiers that make those up (fixed modifiers being a better solution than the stupid RPG solution of adding up penalties for killing peeps and insults - that might conceivably be the issue people have with bars - that they are just a sum). And EU4 is very clever with balancing those modifiers, and limited the amount certain things can contribute to them, and having them rightfully decay (or not as the case maybe).
And when I can see the relation, and know what is contributing to the relation, I don't have to wait until Genghis attacks to find out he doesn't like me. I can take the hint (again abstracting over tensions and giving the player some of the nous that a world leader would have over foreign affairs) and change my religion and mollify him before it happens. And that's a fantastic result - a possibility and a choice that would simply not happen otherwise.