WHOA 25 pages! Okay let me put this thread to bed, once and for all...
Heroes of the Storm sounds a lot like "sons of the storm". What's sons of the storm you may ask? Here's a link to their page...
http://www.sonsofthestorm.com/
It's Metzen, Samwise, and other guys from Blizzard creative team. You can blame Samwise for Pandaria btw lol. They do the art work, concepts, and lore of Blizzard games. SO, in "Sons of the Storm" the storm is Blizzard, and sons are the creative team that makes games we all know and love. What's this have to do with "Heroes of the Storm?" Well, if the storm is Blizzard right... and it's a game with "heroes" right??? Then we can safely assume this is the final name for the Blizzard MOBA they have been working on formerly known as Blizzard DOTA, or Blizzard All Stars. Which both are pretty unexciting names compared to Heroes of the Storm for a brand new DotA like game.
So, I'll say it again... This is the Blizzard DotA game they talked about a long time ago, now with an official title that probably will be officially announced at Blizzcon. This is not the new WoW expansion (thank god), I'm still sitting on the The Dark Below being the next expansion and here's why...
Besides all the obvious reasons you've heard already, here's some interesting things added in 5.4 to reaffirm this as the next expansion...
http://wowpedia.org/Timeless_Isle
If you explore enough of the Timeless Isle you will notice there are lots and lots of Pirate themes. A south seas pirate ship, a sunken ship with ghost hozen, another sunken ship with a chest in it. Two, yes two under water caves with mobs and treasure. A ghost ship boss, a whale shark, and a Kraken boss. What does this all have to do with The Dark Below? Well, as you may have noticed earlier, Blizzard said in interviews that the Timeless Isle is a sort of "experiment." I'm speculating it's an experiment in end game, AND more notably an experiment to how players react and respond to all these underwater and oceanic themed bosses and areas! You see, in video games, developers groom us to get ready for the next challenge. A sort of video game foreshadowing if you will.
Classic had signs of this, The Burning Crusade had this, Wrath of the Lich King had this, and Cataclysm had this. I'm almost certain that The Dark Below is real, and it is coming = D.