Here's the thing, the comparison you made to your own experience in Oblivion is completely off-mark. This thread isn't about wether or not the game should give you extensive exposition on background that, if known, would enrich a player's experience. This thread is about the game failing to convey information about something it, itself, is trying to treat, namely Shar.
In other words, this is not A New Hope not telling you the code of the Jedi, or of the Sith, or about the events of the Prequels. That stuff doesn't matter as far as the story a New Hope tries to tell goes. This is a New Hope completely neglicting to sell you on the Force -- what it is, what it means and what it does -- because whatever, they'll figure it out. And if not give 'em postcards, it's all the same.
Like, staying with this example, if George Luca had done that, and hadn't he hired Sir Alec Guinness to do precisely just that -- sell the audience on space magic -- i'm pretty positive Star Wars would be remembered as A New Hope, some wonky sci-fi movie from the 70s.
Good writing, really, is what it comes down to, and giving the viewer/reader/player every tool they need to comprehend and appreciate in full the story you set out to tell them.
