Wanted to get this out there in case it wasn’t common knowledge yet.
To activate the Mechagnome race you no longer have to do Mechagon. The questline for it has you do it with the NPC’s so it’s no trouble at all.
As a Horde player you only need to have Mechagon at Exalted. Log onto your level 50 or higher Alliance Player and follow the questline starting at the Stormwind Embassy (it’s already marked on your map in the Northern part of the City).
Hope this is helpful and it’s kinda fun to do anyways. Plus you get another Mount and a whole new Race.
Enjoy!