RPGs: difficulty and headroom

This may interest you: http://nethack4.org/blog/strategy-headroom.html

The article defines "headroom" as  follows: if the choices a player can make in a particular situation have a wrong answer, that is a sign of low headroom, especially if a different situation would have a different right answer. 

Has some applicability to RPGs (stat roll = low headroom, point buy = high headroom) as well as general difficulty level (5E in general is very high headroom, but so is Master of Magic).

D&D skill checks: negotiation and adjudication

One of 5E's issues is that the canonical loop goes:

1. DM describes situation

2a. Player declares intention and approach

2b. (Optional) DM rolls dice or asks player to do so

3. DM narrates outcome

The problem is that because skills in 5E are partially overlapping, (2b) should really be a dialogue with feedback loops for player suggestions and not just a query for a number result. Example:

1. DM, "As you're having tea with the Goblin King, you suddenly notice Rincewind behind him, stealthily descending the exterior castle wall. The Goblin King might turn around and see him at any moment."

2a. Lady Sarissa: "I turn up the charm to distract the Goblin King. Smiling broadly, flirting, laughing and touching his arm, trying to keep him looking at me and not behind him."

2b. DM: "Roll a Charisma (Deception) check, DC 15."

2c. Lady Sarissa: "I am proficient in Performance. I think that means I am skilled in holding an audience's attention. May I substitute Charisma (Performance)?"

2d. DM: "Actually that works even better. DC 12 in that case."

2e. Lady Sarissa: [rolls] "11!"

3. DM: "Laughing heartily at one of your jokes, the Goblin King accidentally knocks over a glass of water on the table between you. 'Excuse me,' he murmurs, and turns to call the steward to clean it up... which Rincewind right into his field of vision.'

4a. DM: "Rincewind, make an Wisdom (Stealth) check please to see if your ghillie suit camouflage is good enough."

4b. Rincewind: "Can I do Dexterity (Stealth) instead?"

4c. DM: "Not in this case because you're in plain sight. If your camouflage is good enough it's possible to be mistaken for a section of plants, and I'll waive the Dexterity (Stealth) check because all you have to do is hold still, but if your camouflage is faulty then you'll be obviously not a plant."

4d. Rincewind: "I made the ghillie suit with Woodsman's Tools, and Sprocket helped me look for any flaws in it. Can I use his Wisdom with my Woodsman's Tools proficiency?"

4e. DM: [thinks] "Sure."

4f. Rincewind: [rolls] 19.

5. DM: "Sarissa, the Goblin King waves the steward over. The steward wipes up the mess while the Goblin King continues enjoying your company. He doesn't seem to have noticed anything."