Oh, Teldrassil and the Great Trees (also planted by Fandral^^) may have a much bigger problem, and possibly Nordrassil too. While the actual Dreamgate at Teldrassil was removed, because that branch of it was too corrupted to be saved, the other trees were, like Vordrassil in Northrend, all planted over Saronite and still retain those Dreamgates to this day. All those trees may be happily mingling Old God blood with the Azerite they suck up. So like some other things on Azeroth, they may have been a valuable asset at the time and also absolutely crucial for keeping Azeroth safe, but that may not be the case anymore.
But for now, we can only guess and I think it's better if we guess without incorrect information in the mix. Otherwise it becomes a sudden 'retcon' or something that Teldrassil is supposed to be a normal world tree. And burning down a world tree should be something that is not done without someone to close the wound that leaves in Azeroth, if you care about Azeroth's well-being.