Core Resolution of Dice as Difficulty

It's been a while since I made an article. I had two ready since June, but I've had hardly any time to stop for a while now. I'm just gonna spill this thought out of my head without making it a game. Welcome to CRoDaD.

Core Resolution of Dice as Difficulty

The premise is simple: It's a roll under system, except the die you roll is determined by the difficulty of the task at hand. The difficulties are: Trivial (d4), Medium (d8), Hard (d12), Arduous (d16), Unfeasible (d20). Yes, I know d16 isn't common, you could drop it if you feel like it.

Example: The player character approaches the guards, wishing to enter the castle. The guards won't allow anyone in. The player states they wish to convince them. The GM judges the difficulty to be Arduous, so the player rolls a 1d16 and tries to get a roll under.

But Why?

I was in part inspired by the video from Tales from Elsewhere about fudging. I figured I'd try my hand at coming up with a core resolution that fulfills two requirements:

• Transparency. The player could calculate the odds of success before making the roll.
• GM Dependent. The player can't just make the roll, resolve it on their own, and announce the result before the GM says they get to do that.

Can the first one be solved by the GM saying "The DC is this"? Yes, but the GM doesn't have to do it in most cases. Can the second one be solved by proper tabletop etiquette? Yes, but I wanted to do a thought experiment here.

This is why it's designed like a box with two locks - you can't open it until both parties do their part. The GM has to say what die is getting rolled for this, and the player has to make the die roll.