I feel like the games of Straight Pool 14.1, One Pocket and Rotation are the best games to test a player's overall range of game playing skills, mental strength, and analytical analysis of a given table situation. Play those games in a drawn out match or tournament competition and the best players with the best skill set will rise to the occasion.
It is unfortunate that of the 3 games I list, Rotation is one game that just is not played anymore. U would probably have a very hard time trying to find a mere handful of young players that have even heard of the game let alone play it. Which is really kind of sad because Rotation is a wonderful instructive game to play.
The other games of call 8 ball, 10 ball and 9 ball have their place in the pantheon of pool games. And I list them in my order of preference of play. But I feel that if u can establish ur mastery of Straight Pool, One Pocket and Rotation, then all the other games become just a basic skill test.