I suddenly had a “vision” about good game design.
Games with extremely good design are Nintendos Mario and Zelda games and also Portal.
The controls are simple and the rules are easy to understand. You need your brain to figure out how to use the abilities of your char to overcome the obstacle in front of you. At first you say “Oh crap, how am I supposed to get there?”, then you feel clever when you find a solution for the problem and later you feel super clever when you find out how to avoid the problem in the first place. You learn new things, discover new places or beat new enemies all the time and you enjoy doing it. Basically all of Portal is a tutorial how to play the game but its still lots of fun to play it.
These games give you relatively few tools or abilities, but all of them are useful, though sometimes it takes some time to find out what they can be used for.
I know this is a different genre.
But these games are easy to get into, you learn a lot while playing and you enjoy doing so.
On the other side pathfinder puts a huge entrance wall in your way. First you have to understand the very complex rule set in order to enjoy the game at all. Until you understand the rules playing is just super frustrating.
And once you understand the rules you realize that you can totally ignore half of the classes, feats and spells at all.