We know that Blizzard has planned to put Mekkatorque in Heroes of the Storm for a long time (Since 2011 at least) so why wait? My first thought was that they wanted to wait until the HotS meta was in a certain place for some reason.
But does it make sense to hold a hero until either a counter hero, or until a certain map has been released first? Any new hero that is added needs to function on all the existing maps without breaking them, and will need to be countered by multiple heroes that already exist.
It could be they are waiting for Mekkatorque to do something in World of Warcraft. We’ve seen Mekkatorque in his new battle suit. I wonder if he has some kind of upcoming scene where they will show him doing things that they want to bring in to HotS, but they don’t want to spoil what’s going to happen for World of Warcraft players. Admittedly, that’s a reach, and might be 100% wishful thinking, but the idea of it makes me excited for BOTH games.
Maybe they want to make him a multi-class character, but that he got too complicated. Now they are watching how Varian does. Working kinks out of the multi-class concept with a straight forward character before trying a more complicated one. As a bonus, they get to test the waters for how multi-class characters are received, and get us the player familiar with the basics of how the system work before adding a layer of complexity on top of it.
Of course, this is all assuming that Mekkatorque hasn’t been scrapped in favor of Chromie. I highly suspect that the HotS team would like a character that represents each race and class from WoW and that Chromie ticks the ‘gnome’ box. Datamining had shown Mekkatorque with a ‘tar barrel’ attack that might have turned in to Chromie’s Slowing Sands. Chromie also has the Gnomeregan score as her theme music instead of the Caverns of Time music. Doesn’t leave a lot for future gnomes.
The worst part is I can’t just say “we’ll see” because if Mekkatorque is never released, we could speculate forever. On top of that he could get scrapped, and then picked back up later for a completely different concept. HotS is so random I am completely unable to guess what character might be coming next.