Long jumping in 5E says you can jump a distance equal to your Strength score with only a 10-foot run up. First, yes, it is simple. I get that (again) is the design goal for 5E, but it is frankly ridiculously simple. It falls apart on so many levels:
- The run-up is not nearly long enough. And the Athlete feat reduces it to just 5 feet!
- There is no rule for jumping further, which is most certainly possible, even if you don't consider professional jumping/records.
- This is nothing about jumping while unencumbered, encumbered, heavily encumbered or anything, and how that should modify the jump distance/difficulty.
- And more...
Now, the only basis I have is humans because those are the only common factors between real-life and the fantasy game.
For instance, when carrying my backpack (about 20 lb.) in high school I could "leap" over a 15-foot ditch near my school with about a 40-foot run up. My Strength was probably a normal 10, but I certainly had proficiency in Athletics with all the sports I did and working out.
There is simply no way using the super-simple RAW for long jumping to model that. The DM has to make up rulings on the fly, and most DMs would approach it differently, despite all using the same base RAW for it. Or the DM just says you can't do it because the PC has STR 10 and it is a 15-foot distance.
So, D&D or another game with "better" rules geared towards simulating action, combat, and other factors is what I was looking for.
EDIT: I will grant that at least under the Athletics skill it stipulates you can use Strength (Athletics) to "try to jump unusually long distance", but fails to specify what qualifies as that or how you would do it.