Okay, I did some research. According to Alex Afrasiabi's Twitter (
https://twitter.com/Alex_Afrasiabi/s...87858604802048 ) BFA takes place in 33.
Wrath of the Lich King took place in 28, with the Cataclysm soon after. Legion is set four years after that, as mentioned by Magni and the Frostmourne questline.
As such, Legion would take place around 32 and 33, meaning that the warpath did indeed happen very soon after and that there is very little time between the Legion's defeat and the scenario we are talking about here.
Of course, all of that only applies if Blizz did not retcon stuff again without telling us. Which video exactly do you mean? I don't recall this specific a mention in the one where Jaina talks while Teldrassil burns.