I want the rules to be short. Old rpgs had very short rules. As I mentioned in another post the whole rules of RQ2 was like 100 pages and the rules part of third edition of Call of Cthulhu is like 35 pages long.
The game mechanics should be fast. Minimize the math and the number of rolls needed.
This will be hard for me to accomplish. It is so easy to add rules for this and that. But I will have to try. The old school rpg rules was simple (and sketchy at times).
This is the whole point of doing an old school rpg. The rules should be recognizable and give the players that special warm fuzzy feeling of home. Even if we add some twists to them.
Prevent power gaming
I have never liked power gaming. It sucks the fun out of gaming. I think this means less player choice during character generation (haters will hate) and character improvement.
This is a bit contradictory as the game should be old school. But I feel that some recent rpg innovations can well be incorporated into the game, as long as those innovation does not take away the old school feeling.