Don't understand why the dev have to "prove" something. No matter where you got the sneak preview, it is still a sneak preview.
Even for product launch like handphone or wearable devices. The actual device usually is very different from prototype.
I don't get why people get so agitated over it.
Heirloom set is explained in game(not the first time), actual stats are shown in game. What other explanation is needed.
No wonder no more teasers in Instagram... All those foolish people think skills from demo builds are confirmed ones...