This is such a mess, hahaha. So many roles are being crammed into as few characters as possible. Even settings are getting exchanged for others. "Where are we now? Not the Rhoyne" says Tyrion. Bahaha. I feel like at this point, they just have little highlights from the book in mind that they end up cramming into whatever corner they can while everything else is different or entirely the opposite (e.g. Daenerys' marriage idea).
Also, isn't sailing into Valyria supposed to be a big fucking deal? Like, a "no one ever returns" kind of big deal? Seemed strange that Jorah would assume there would be nearby fishing villages next to the fantasy equivalent of the Dead Zone. Or that he would attempt to sail through it in as shitty of a boat as that.
Yes. No-one has come back from the Doom of Valyria. Except Jorah and Tyrion from the show and maybe Euron Greyjoy, if he's telling the truth. In the books, Valyria isn't a quiet, overgrown city of ruins. It's said to still be shaking from ongoing earthquakes and volcanic eruptions. The smoking sea supposedly has poisonous fumes.