D&D 5E Unified Weapon and Skill System

[Ahnehnois]

The problem with heavy d20-based skill systems is that they just don't really work.

The difference +1 makes is 5%. That means you have a 5% better chance to make the target number.

The difference an extra die makes when you need 3 successes in Exalted is 0.4 successes per die.

Even if you do a 3 stage graduated system of 2/4/6 that means that the best person in the entire world with swords has a 30% better chance to hit than Quincy the farmboy.

If you switch into 3E style of '1-20 hurr durr' you get all the flaws of 3E's skill system (including its wholesale slaughter of many roleplaying opportunities).

D20 is just not a great system to use with a skill-heavy system.

I think you're not entirely wrong. I think part of a flattened math system could address these concerns though; instead of numbers increases as one levels up, more rerolls, take 10 and the like, and other nonlinear improvements.

With regards to fighting there's also weapon proficiency, which provides an excuse to penalize Quincy the farmboy so the difference is greater than 30%, as well as ability scores (and if Quincy is a big farmboy with 18 Str, he ought to be at least somewhat dangerous).