My experience of doing homebrew in 3e made me conscious of the holistic nature of the rules in 3e, and now in 5e. I believe that much that seems vague is more a result of overlooking context. These are extensive, sophisticated games systems, by veteran designers, and although it may seem that the rules are modular in approach, they are instead holistic.
To understand
Jumping requires attention to multiple parts of the rules, which I think might be grokked by considering their absence. Say the text under
Special Types of Movement was absent. The "
unusually long distance" text under
Athletics would be ambiguous: what is usual? Add in then the text under the
Jump spell which tells us that "jump distance" must be a value that can be
tripled. An ambiguous value cannot be tripled! The holistic context tells us that somewhere, somehow, a player has a definite number for how far they can jump. Consider then the "
an effort to overcome a challenge" text under
Ability Checks. That connects with the
Athletics language that you "
attempt", "
try" or "
struggle". Holistically, the text entails that there are two kinds of jump distance to consider. A usual distance, that can be tripled, and an unusual distance. Again, you can't triple an unusual distance because whatever value you pick, you can pick a value 3x greater and with as much justice call that unusual! Elsewhere,
Second-Story Work tells us "
when you make a running jump, the distance you cover increases by a number of feet equal to your Dexterity modifier". Again, this helps define the difference between usual and unusual distance, because it is meaningless to add Dex modifier to a distance which is an arbitrarily picked value. When choosing between an interpretation that renders some rules meaningless, and another that gives meaning to all rules, preference is given to the latter. Once we insert "up to your Strength score" as usual, the whole system works. The mechanic can really only be said to be vague when we can insert an alternative term matching the language, and show that an alternative yet consistent system is yielded. And that is why the
Magic Missile text makes sense, of course.
Taken together, the Jump rules are not vague! Knowing what DC to assign to an unusual jump is left to the DM because "
For every ability check, the DM decides which of the six abilities is relevant to the task at hand and the difficulty of the task". They're not vague, but they intentionally leave choice of DC up to the DM. They do guide to the range for DCs, and in the DMG we're guided further as to what each category should mean given a baseline D&D world. You can see the issue here: rules in 5e can seem vaguer than they are because it's a heck of a job to know the gestalt.
The context in the text is not a sufficient explanation, of course, because every player of a game brings additional filters in the form of their understanding of language, culture, logic and so on. It is the joint context, textual rules and internal filters, that tells us what we think it all means. The authors of 5e, in using natural language, are acknowledging that internal factor, sited in the player, and that they cannot control it because it arises from education, culture, etc, etc. They say that they want to provide a foundation - something solid to guide players as to what, with their expert experience and craftsmanship, is going to work well at the table. Frequently, they get that right
