Rarescape Design Goals
Compatibility with D&D — ability to use a Rarescape character in the same game as standard D&D characters, or use a D&D Monster Manual creature as a Rarescape adversary.
“5e Rules for Every Genre™”. Support all top genres: Pulp, Fantasy, Sci Fi, Cyberpunk, Supers, and Horror
Seamless wargame variant. Ability to use system for a miniatures game (like Savage Worlds ‘Savage Worlds Showdown’ PDF). Ability to move between miniatures wargames and roleplaying games. Within roleplaying games, ability to alternate between using miniatures and theater of the mind.
Use any types of miniatures (or none at all) — use a Grid, hex, 15mm Rulers, 28mm Rulers, or Zones
Family friendly content and artwork
Inexpensive core rulebook to increase adoption.
Generous fan and pro licensing (like Savage Worlds)
Digital versions (PDF, maybe Roll20).
Eventual ADA accessibility
Quick to learn if you know D&D
15 Minute CharGen
Avoid different rules subsystems. Have starships rules follow character rules.
Avoid unnecessary bookkeeping. Maybe have powers be ‘once per scene’ versus using Power Points.
Fast game prep due to tie-in to adventure location cards and background cards
A Rules Reference not a How-To-Play-RPGs (see Mike Mearls twitter posts on how people learn games).
80/20 rule — 80% of types of characters can be created with 20% of content
Concise rules — 96 to 150 pages, 6×9” or so format
Basic Character Sheet Could Fit on a Playing Card, and all the rules for your powers could fit on a single page of paper.