Many of the systems and rules I’m developing for my game are designed with the intent to make it possible for “anyone to play.” This means a bunch of different things so I’m going to talk about the mechanics of “letting everyone play.”

Bounded Accuracy
This isn’t really a thing, but 5e is making it a thing. What “bounded accuracy” means is that unlike 3e/4e, attack and defense bonuses won’t scale with level. This means that a 1st-level character can probably hit a 30th-level character.

“How effectively” is all up to the damage dealt.

Hit points and damage will still scale, in spite of accuracy remaining about the same throughout the levels and tiers of play. That means a party could be broaching Epic tier when a new 1st-level PC joins them.

That 1st-level PC will be incredibly fragile compared to the others, but if the player plays intelligently, they can fight alongside the others. Then again, the world is full of 1st-level characters, so it might not be so dangerous.

Guild Wars 2 introduced a system called “Side-kicking” which would automatically scale players up or down to an area so they could play with their friends. You may not have known this, but 4e had a similar system that no one ever used.

Honestly — the so-called “bounded accuracy” concept solves so many problems I can’t even list them. You never have to worry again about your party members “falling off the RNG” as it’s referred to in the Character Optimization forums.

“Leveled loot” is no longer necessary. The “feat tax” becomes a problem of yesterday. “Encounter balance,” and coming up with monsters to provide a consistent threat? Not a problem. I don’t think any of this is new.

There are really only a couple problems left to address.

Power Sources
This one is more abstract but represents something too, which Wizards of the Coast is unfortunately dropping from the next edition of D&D — power sources.

From one perspective, powers sources reflect alternate paths to achieving power in the game. Whether it’s swinging a sword day in and day out, to spending years of studying the arcane arts, to offering prayers to your deity — power sources are the methods by which characters attain the powers they need to adventure.

Why are these important?

Because power sources were the single best, in-universe explanation for how PCs with vastly different ability scores could fight alongside one another.

Magic-users had Intelligence for their basic attacks, Priests had Wisdom for theirs, Thieves had Dexterity for theirs, and so forth. No worries about spells-per-day or limited use this or that. Everyone could “swing a sword” like a Warrior — in their own unique way. WotC had a great thing going here.

The main problem with 4e’s power sources is WotC didn’t plan far enough in advance. Wisdom is favored above all others, and some of the other abilities are very poorly covered. Then, there’s no option for “No Ability” builds.

Not everyone wants to leave elements of their character to chance — this is evident enough in the popularity of “Point Buy” systems. There’s a way to make everyone happy at once, and that’s by providing access to power without requiring probability to enter into character creation at all.

There are other important mechanics for making it possible for “everyone to play” but these are at the core of both the math and the setting.