when is have a look to the Manual / ingame instruction of Age of Wonders 3 for example or remember civ5 cyclopedia that´s really nice to have!
From my Point of view, with more Details you will get a better understanding and if you really understand the Background, stories, chars, doings, relationships and history you identify more with the game and chars, you play with more Passion, ist not only Pixels...
of course there are much Information in the game and detailed dialogs, but just a few People can remember all the "walls of text" for the rest of the game from each npc, right ?