Let’s set up some design goals.
It’s a game - it’s not a movie or novel; the setting is not about telling a great story, but about equipping the players to tell their own stories. It should be open-ended and diverse; there isn’t one central story, but a series of interconnected stories that allow the player to jump into it anywhere. It’s not about the humans defeating the bad guys. It’s about an ongoing, unending series of conflicts that the player characters find a way to navigate within.
Use the system as presented in Tales of the Splintered Realm, but not be beholden to it. Freedom to manipulate the system to better fit the narrative. For example, I’m thinking of bringing in some elements from Sentinels of Echo City; I am thinking also of bringing in some things from Army Ants (getting more actions per round; weapon tinkering rules). It’s going to be a ‘greatest hits’ collection of the other games I’ve done.
Maximize value. In reviewing the first edition of Shards of Tomorrow, I noticed that I created new mechanics for different situations; just looking at spacecraft, there are different ways to resolve hit dice, values, upgrade costs, and maintenance costs. Since we already have one random element (hit dice), this same value can be applied in different ways; weekly maintenance can be hit dice in credits; upgrade costs can be hit dice x10.
Maximize space. I want this to be 64 pages, and formatted as Tales of the Splintered Realm, but have EVERYTHING for the full game. Rules for character creation, advancement, technology, creatures, vehicles, setting, and a solid starting adventure.
Art. I have to accept that art matters. Presentation matters. The visuals matter. More illustrations, and of the highest quality I can muster.
Take my time. There is no hurry to get this done. I want to take my time with it. If it takes six months, no matter. It’s about the process, not the product. I like tinkering with systems and writing rules. I may as well spend time doing that.