Glyfair
Explorer
One thing to remember is that a lot of games had new editions that you might not notice, especially in the early years of roleplaying. Runequest, for example, had almost no significant differences between 1st and 2nd edition. 3rd edition, on the other hand, had a lot of gnashing of teeth. It was made worse by the fact that it happened at the same time as Avalon Hill took over publishing it (even though Chaosium made the design decisions that were causing teeth gnashing).
The first RPG, outside D&D's odd example, I remember with a significant change was Champions. First and second editions were released within a year of each other, IRRC. We did adjust pretty well, though.
Why did those changes often go well? Because RPGs were often rushed out the door unfinished. If they weren't they wouldn't ever be released (see Hero Wars). The second edition was often the "final draft" of the first edition. Changes were overwhelmingly fixes of major problems, and not new approaches to the game system.
The first RPG, outside D&D's odd example, I remember with a significant change was Champions. First and second editions were released within a year of each other, IRRC. We did adjust pretty well, though.
Why did those changes often go well? Because RPGs were often rushed out the door unfinished. If they weren't they wouldn't ever be released (see Hero Wars). The second edition was often the "final draft" of the first edition. Changes were overwhelmingly fixes of major problems, and not new approaches to the game system.