All games have to start somewhere, and I, even as a naive 19yr old knew that I would not be able to begin with nothing.
So, over the next few years, I played (and researched) in this order: Dragon Warriors, Dungeons & Dragons, Warhammer Fantasy Roleplay, Rolemaster, Gurps (fantasy), Traveller, Vampire(VtM) and Shadowrun. I then borrowed and read the base rule set for several other games, including some niche games, such as Tank Girl & DragonballZ.
By 19, I was 4 game systems into this list. I came to Warhammer via HeroQuest & AdvHeroQuest, which we a very clever marketing system for Citadel.
So I had these basic ideas: The game system needs to be rules lite in the basic design, so players can quickly make choices. Attack vs Cast spell vs Heal vs Run away, but I roleplay needed more choices too, rather than 'roll charisma'
How many times has it happened: I try to seduce the girl, roll: 20! crit, she succumbs to your charms and you bed her that night.. if only it were that easy, you'd just go into a club, say 1 line to 20-30 girls, eventually you get a crit20 and you 'win' (or in the new systems, take 20)
The game system needs to have more reality to it.
Not in the sense of story, play or otherwise, but the underlying maths need to be mathematical, the structure of the rules need to make sense, so that any human being can make choices in the world, which are logical, predictable and would react the same way in real life & game play. This gives players a nice sense of 'grounding' to work from.
Not having that grounding has always caused ire in games, both from my own experience, and told to me at numerous conventions.
I had a game where I was playing a Vampire, who could speed up to perform multiple actions. I kicked a cup at my enemy, expecting it to fly across the room at heightened speed (or shatter and the peices fly across the room) but as soon as it had left the tip of my foot, it slowed down to normal speed.. the roleplay was broken by the rules (yes I know GMs should, but often side with rule books until they get more experience) an argument ensured, and the entire nights RP was soured by the lack of trust I had with the world.
So I needed a system that would follow the laws of physics from the start, THEN we could bend the rules for magic etc.
Lastly, I wanted my game world to be both dynamic and static. I can not tell you how many times I felt that the GM was pandering the players, to the point of frustration. (I have also fallen into the GMtrap, players conciously or subconciously become stupid if you let them get away with it, it also spoils the game). Usually this was because the GM had picked a campaign that was too high for the players, or too low, and had to scale it. Sure, a well written campaign can be 'scaled' but as often as not, the scaling causes things to be too easy, lulling the players into false securities, or too hard, causing them TPK more often than not (Why do players decide to keep going, when they probably know they're going to die?)
Probably because I was running a club, where each week I might have a whole new set of players, repeatedly starting campaigns, never finishing the storyline. I began to structure the game in sessions: If you got out by the end of the session, you lived for another day. If you failed, rock falls TPK. Players would look at the clock, and begin thinking about how to get out (one exception. If ALL players turned up the next week, we'd do a 'to be continued' ending)
But this created a sequence of events, in which a group of adventurers would come into the first room of a dungeon, clean it out, loot the room, then realise they were too damaged to continue, and go back to town to regroup, resupply and think it over. The following week, a new group, some of the same players, some new, would return to the dungeon, the older players would explain to the new what happened, and what they intended on next. Sometimes new players would provide new skills and find hidden treasures, or work out a puzzle to help the older team get through without harm (yes, sometimes old players would quickly make up a character relevant to the quest,just for that session, so they COULD figure out the puzzle).
" Sir Baldwin, Hector and the Bard Zafrodi realise that their quest has come to a premature end. The Puzzle on the door is far too archaic to understand, they return to the city of Malthue and seek out a wizard. Hector, having some duties with his lord, agrees to meet them in a weeks time, leaving Baldwin and Zaf to find a suitable candidate. Along comes Hwentil the Shaman & Mystic, who mysteriously knows the Archaic Language of Hui'k Lui'k and together they figure out the door puzzle, and dispatch the undead they lie in wait behind the locking mechanism"
This meant that the world lived on between adventures.. that between the sessions, people were getting on with their medieval lives, and that was when I began to track these NPC lives, their politics and the world at large.