While I generally like how skills work in D&D 5e, I do have a few criticisms of it. These are mainly due to some skills being egregiously more useful/common than others (Animal Handling vs Perception, or Nature vs Stealth), but those criticisms are not what this thread is about.
This thread is about how skills are simplistic. In most cases, you're either proficient (in which case you add your proficiency bonus to ability checks that use that skill), or you're not (in which case you don't add your proficiency bonus). There are some outliers, like the Bard's Jack of All Trades feature or Expertise, but they're still really simple. And this is great for many new players who just want to learn how to play the game. However, I've lately found it increasingly boring. I want a bit more diversity. Tasha's has helped a bit in this matter by allowing more people to get Expertise (through the Skill Expert feat and the Ranger variant class feature, Deft Explorer), but there still isn't that much to it in 5e. I feel that if there was just a bit more oomph, characters could be differentiated through their skill bonuses a bit more.
And while I was thinking on this, I came up with the idea of Skill Deficiencies. Upon character creation, you choose a skill that you aren't proficient in, and you make that be the skill you are deficient at. A Barbarian would likely choose Arcana or History, a Wizard would probably choose Athletics or a Charisma skill, and so on. IMO, something like this would make it a bit more fun roleplaying certain characters and interactions between party members, like a Rogue teasing the Paladin at being the literal worst at Stealth checks (due disadvantage on Stealth if they wear Heavy Armor, and having Deficiency in that skill), or a Lorehold Strixhaven character teasing a fellow party member about failing their History class. Although I liked the idea (and still do), I am yet to figure out how it would work mechanically, and would like to see how others feel on this matter before I implement a house rule at my tables.
My first idea was pretty simple and obvious: have characters subtract their Proficiency Bonus (or possibly half your proficiency bonus) from ability checks using skills that they are deficient in. However, this quickly comes up with a strange conundrum; why would you get worse at the skill as you leveled up? Why would a barbarian that's bad at Arcana have a worse bonus to Arcana at level 20 than they did at level 1?
This then brought me to consider a change to their skill deficiencies that doesn't change as you level up, like a -5 to that skill or disadvantage on all ability checks that use that skill. However, I'm still not sure which one would be better, or if there's a better way to do it.
Any thoughts? I'd appreciate some feedback, and any experiences that DMs/players have had with similar features. Do you think that this is a good idea or a bad one?
