Exactly. As soon as you say "Hey, we're working on a Dragon-based class for 10.0!" You've crossed the Rubicon into violation territory, and if Gleepot's story is true, the Rubicon was crossed over and over again. So why is the name of the class and race suddenly off-limits? If this source is willing to break the NDA on 10.0 and even 11.0, then giving you the names of the next race and class shouldn't be a problem. You want to know why it's a problem?
Because it's fake, that's why. Again, a group of forum users would have great difficulty coming up with a name for a future dragon race or class, but a Blizzard dev would not. If a Blizzard dev is dumping this much information on you, they're going to tell you what the next race and class are called (or you're going to ask). If you're going to ask the status of Dark Rangers and Tinkers, you're going to ask what the next race and class are called.
And btw, if you're worried about getting your source in trouble, you wouldn't be posting this info on a forum in the first place. Just saying......