Retcons, or retro-active continuity, are a thing of life. They are a disturbance in the space-time continuum, a great force that carries with it the power of a god-like being (cough, Q). One day you'll be reading that Rhonin the Prettiest Mage of Mageville is married to the angelic Night Elf ranger Vereesa Windrunner, and the next day you'll suddenly be reading that Rhonin is really a barbarian demigod who's having an affair with the dominatrix Mistress Windrunner at Gil Grisert's place.
All that stuff about Rhonin being awesome? Yeah, never happened.
Retcons are employed as a writer's way of changing lore elements that don't necessarily fit with the story they want to tell now. The writers of Warcraft lore, especially Knaak, don't do this to be mean or because they're dumb, they do it because the story is more important than unmodified continuity. It's their universe they're writing in, and at least in their eyes they can play Q. The problem is when a universe like Warcraft starts to have tens of millions of fans, and those fans become so heavily invested in the universe that they make it their own. This isn't a bad thing by any means, but it does lead to those fans becoming upset when things change all the sudden.
But, such is life with WoW. The game is fluid, ever changing -- both in lore and in mechanics. It's best not to complain about it, just go with the flow and enjoy the story.
"Why doesn't Blizzard sell gold? It would take away business from the other gold sellers and potentially even shut them down."
Blizzard is against the trade of virtual gold for real money. There are legal reasons, and there are ethical reasons. Plain and simple.
Blizzard certainly could begin selling gold on their own, and in the process shut down a ton of operations that farm and sell the stuff. But here too, are many gray areas. While some gold sellers would fold if Blizzard setup their own gold selling service, others would just undercut Blizzard, leaving them as the lowest price and the most economically viable solution to gold buying. Resulting in all of this could be a gold price war, in which the value of gold continues to decline; eventually making the currency completely worthless. This would entirely destabelize the economy in the game, and would have a rippling effect in other areas, since raiding, leveling, and PvP ultimately tie back to needing vast amounts of gold to be done at a high level.
At the end of the day though, it's very simple. Blizzard will not sell gold because they are against the trade of virtual gold for real money.
End. Of. Story.
"In 'Day of the Dragon' it's pretty much implied that paladins hate mages. Do we have to accept that as canon or was it just a case of Knaak being Knaak?"
I think it's fair to say that the paladin order doesn't approve of manipulation of the arcane in the ways that mages do. Does that mean that paladins hate mages? No. Does it mean that they're not entirely happy with the path they've gone down? Yes. Are they going to refuse a sheep or the well timed frost bolt? Absolutely not.
"A buddy of mine told me that casting instant cast spells on the run slows you down. Am I being had or did I just never notice this?"
Your friend, as they say, is full of it. Casting an instant cast spell does not slow you down. It might, maybe, possibly cause your video to lag a moment, but you'll keep running as long as you're directing your character to run.
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