You're forgetting that Pandas were an Aprils Fools joke too at some point before becoming real. If anything, its Blizzard saying hey...we read the leaks on MMO-Champion so now we're gonna troll you with our April Fools Tinker tease. They are not stupid they know what the players want. If anything the Tinker nod might be more official proof than ever before.
Also on March 17th, why would offical World of Warcraft tweeter account tweet "Did someone say Goblin Mode?"
https://twitter.com/Warcraft/status/...UrrH2X0AVpOrhA
Adding new Specs won't be interesting enough in my opinion, you'll still be playing same class with some new toys and that's it, it won't truly feel unique. Also, if Dragon Knight is another Spec who would even get it? Warrior already has a tank spec, what is the point of having a 2nd Tank spec? One uses Sword and Shield and other Two-Headed Weapon? If I wanted to do that I'll go role a Blood DK. Makes no sense.