iserith
Magic Wordsmith
There was a mechanically small but flexibily large difference in the D&D Next play-test system that became 5e. Skills weren't tied to specific abilities.
So you could provide a critique of a performance with Int (Perform) or look at a blueprint of the estate grounds to devise a route to take the party in unseen with Int (Stealth). Bend an iron bar and use Str (Intimidation). It gave a lot more flexibility. Sure, there's a default for the common use-case, but it handles all of the cases intuitively.
We can do this now under current rules. DM asks for an ability check, player asks if a particular skill applies.
Basic Rules, page 58: "Sometimes, the DM might ask for an ability check using a specific skill—for example, “Make a Wisdom (Perception) check.” At other times, a player might ask the DM if proficiency in a particular skill applies to a check. In either case, proficiency in a skill means an individual can add his or her proficiency bonus to ability checks that involve that skill."
And if that's not specific enough, we also have DMG, page 239: "Under certain circumstances, you can decide a character's proficiency in a skill can be applied to a different ability check. For example, you might decide that a character forced to swim from an island to the mainland must succeed on a Constitution check (as opposed to a Strength check) because of the distance involved. The character is proficient in the Athletics skill, which covers swimming, so you allow the character's proficiency bonus to apply to this ability check. In effect, you're asking for a Constitution (Athletics) check, instead of a Strength (Athletics) check."