A friend of mine had a copy of Wizards, but we never played it because it had a lot of problems. Several of the rules seemed unclear, and the last part of the game (in which players who have achieved the highest possible rank must then chase down the High Wizards in search of Sacred Gems) seemed to take forever. Over time, my gaming group modified the rules a lot, and developed a version of the game that we consider a lot of fun. I'd estimate we still use about half the rules from the original game.
If you have a copy of the game, and are interested in our changes, you can follow this link to a PDF of our reference sheet, which includes all our changes. (If you prefer, you can instead get the PostScript version.) It looks a lot like the sheets that come with the game, except we don't use it for recording tasks or other such stuff that arises in play; we use it solely for reference. (We track durations of animals and events by placing markers on the Calendar track.) Thus we were able to fit in a lot more information.
If you don't have a copy of the game, then all of this is likely to be of little use to you!
One item may look like a change but isn't: the RANDOM WIZARDS table. This is just a way of saving wear and tear on the Wizard cards by using percentile dice (two 10-sided dice; use a white one and a colored one and read the white die first as usual) to select one of the 14 cards at random. If a Wizard or Secret Wizard marker is on the board you have to resort to shuffling the deck as before. (If the only markers are for non-secret Wizards, and no phantasm or trap cards have been removed from the deck with the Wizards, you can still roll the dice and then reroll as necessary.)
The reference sheet also includes some information that is unchanged from the rules but which we found was needed often enough that it was worth having on the sheet: Random Encounters, the order things happen in if you have Multiple Specific Encounters, descriptions of the effects of Animals, etc.
There is a third page headed RULES CLARIFICATIONS, with interpretations and rulings we've made over the years. These are not changes per se, but may differ from other players' interpretations. This section runs over onto the fourth page as well.
The fourth page has two additional sections. OPEN QUESTIONS lists any lingering cases where we're still considering a rules change or an interpretation of some rare situation. The other section describes additional changes for playing the COOPERATIVE VERSION, in which all the players form a single partnership against Evil. After playing Wizards as a competitive game for more than five years, my group started experimenting with the cooperative version around 1997, and now play it that way almost exclusively.
Note: The Cooperative rules in the file are now simpler and more challenging than the version that had previously been posted here. In particular, the players no longer get to draw points from a common pool, which eliminates a complex rule to deal with players who change Orders, and also keeps the partnership from advancing a single player using points drawn from everyone else's efforts. Other changes likewise enforce the need to cooperate if the players are to win before Evil takes over all the lands.
The first part of the PostScript file is my personal tools package for writing PostScript documents. The Wizards-specific part starts at a line that says "START OF WIZARDS STUFF".