If you want to reach the maximum potential of your class, sure, there are number crunchers out there who will tell you the best talent and stat choices to make, spell/ability rotations, etc. But the information you need to be successful in your role is really all in the game. We've gone to great lengths to ensure things are clear enough that you can make some meaningful choices for your character's power on your own, and still have a great shot at catching onto what makes you excel.
If you're speaking at all about boss encounters, I think you'll dig the Dungeon Journal (formerly referred to as Encounter Journal) coming in patch 4.2. Once we're able to catalog more of our dungeons in this journal, you'll get a lot of essential information for each boss fight. It's not going to tell you how to beat the fight, but it's going to tell you what kind of abilities the boss will be using against you. You'll just have to figure out with your party or raid how to deal with those abilities when they're used. Dungeon Journal will also help you find the loot you're looking for from each boss ahead of time, so you have items in mind you hope to get before even setting foot in the dungeon.
One major flaw, no one will read it and then blame you guys for not writing a good enough guide. I can imagine the situation now. "Dungeon boss fight. Let's see. TWO PARAGRAPHS?! Only elitists read that, let's just pull." At least It'll make it so there's no excuse to fail on a boss, and I can rage as much as a want at a failed PuG, (I never PuG since they're so failtacular, but if this dungeon guide comes out, then I might just have give a try to see how many people still can't do the fights even when they're having the hands held by you guys.