Design choices
This version of Warcraft is based on the following ideals. They are sometimes at odds, so I attempt to use the higher rules over the lower rules. If that fails or the result is unsatisfactory, I will keep to personal taste.
Older Lore
The older the lore is, the better it is, at least generally speaking. There are gaps at times when people didn't pay attention even early on. Reconciliation must be attempted.
The Games over Books
This is tricky, but the games should win over what someone writes later on. A detailed retelling of an event in a book is useful, but its failure to keep true to a game needs to be reconciled somehow.
Turtle WoW Is Included
That private server did things right. Its lore should be included when possible. An exclusion here does not mean that it's invalid, but rather it's not yet been written in perhaps.
Keep Within a Time Period
Lore needs to stay within the bounds of Wrath of the Lich King preferably, likely before late 2010. The lore begins falling apart very quickly after this point. It's vaguely acceptable to pass beyond this point for minor things, such as usage for an already existing herb, but it's unacceptable to add new continents or unadapted plot points.
Biology (Mostly) Matters
The story should be internally logical. A small, pregnant woman will not toss a grown man. An army of gnomes armed with knives will not defeat an equally sized army of tauren. Prayer alone cannot save a fight until it actually does somehow.