I didn't realize that this board was actually still open, and PM'd VS an idea that I might as well write out publicly. It still uses a meta-currency, so I understand if you're not keen on it.
Mechanics like Honour are there to get NPCs to like or tolerate you enough for a conversation in the first place, so you want the mechanics to focus on the incentives to speak with NPCs and not the interactions themselves.
Example:
- Get 1 Reputation point with that NPC when you complete a favour.
- Trade 5 Rep points for 1 Esteem point with that NPC's social circles, get more by completing their quests.
- Trade 5 Est points for 1 Fame point in that non-player circle's region of dominance, authourity, etc.
And of course you lose points by failing their missions, besmirching their honour, betraying them outright, etc. You can spend these points at any level if you need to call favours from these NPC's, if it would involve them doing something they'd rather not interfere with for good reason like blood & treasure or their own rep/est/fame.
Edit:
Tbh GM's technically already do this, you usually need to meet a threshold of trust beore an NPC begins to offer the party jobs, but in spelling this out, favours are not rigidly defined as a single unit.
If you really go out of your way as a party and finish the favour or quest with flying colours, that would be worth extra points with the first, though if you underperform you might get no points yet still get paid. You can make no progress, or more than what was asked and leap to the next level in one or two steps.
On that framework, you might instead have Minor and Greater quantum levels of Rep/Est/Fame, and only by outdoing the previous level in quality of accomplishment will you be allowed the next level. With this, a possible adjustment to Fame might be: you can't spend those points/make good on your fame unless you outdo yourself for the social circle in that region, making both you and the NPC famous across the citizenry, residents, etc.