Heroes of the Storm's beginnings are rooted in a mod that Blizzard made in 2010 to encourage StarCraft II players to get into the modding scene. Not only was this unnecessary (the StarCraft II comunity took to modding like fish to water) but the mod gradually became so well-liked internally that proper development began in 2012 to make it a full-fledged MOBA.
At PAX Prime, I asked the team what was going to make Heroes of the Storm stand out from the rest of the MOBA pack -- or whether it was merely content to ride the Blizzard name to big sales. The response was that this game is shaping up to be one of the most friendly and welcoming MOBAs on the market. Gone are mechanics like denying and last hits and in are new concepts like shared team levels. The devs said that the root of the toxic atmosphere seen in many MOBAs is game design that focuses more in individual selfishness and potential ways to hurt your own team. There also won't be any chatting with the opposing team in HotS to cut down on potential sass-mouth.