Made two versions of the Greatest Game System Ever (tm) - GGSE, in response to the horrid AD&D 2nd Ed. Unpublished of course.
V1 - Percentile based, Grand Differential Table, Continuous Action System, Styles. Eventually collapsed under its own weight and complex magic system
V2 - d6 based (dice pool, 6s are success), small number of skills. Had a building block magic system, but usually defaulted to moding AD&D 1e spells. Fast and fun, but not well defined. Dropped when D&D 3.0 came out.
What I learned:
V1 -
1. Too many skills sucks (lacks focus), but like the Novice, Apprentice, Journeyman, Master catagories
2. Used Offense vs. Defense with fairly static HP in an attempt at realism. Discovered the Realism in game mechanic sucks (miss, miss, miss, miss, miss, miss, dead - how droll).
3. Plotting a fight segment by segment is a DM burden.
4. Loved the idea the difference in the rolls influenced the outcome (so a dagger could one-shot)
V2
1. Fast and Fun - much quicker and easier on the numbers
2. Too few skills sucks too.
3. Magic ala D&D is hard to do, that is why they made spells. Building block systems are hard to balance.
4. Having to make everything on your own wears one out.
So, D&D 3e comes out. Having gone through the design process, I loved feats and now appreciate the HP/AC approach (which is why I ignore anyone that uses realism as an arguement for a game mechanic -- it needs to be fun first, realistic second). It had a nice balance of skills.
But then I encountered Savage Worlds and I am hooked. It had the elegance of V2 and the Raise concept from V1. It was like they stole all our (one other designer) ideas and actually made them work

. That has to be the basis for some sort of lawsuit
