As was said before, this was a player-initiated method to avoid Jeuno tax, there's nothing SE can "bring back".
On Leviathan it's in Upper Jeuno atm, and I prefer it that way, both as a buyer as well as a seller. Takes less time travelling there and don't have to zone out and miss shouts/yells. The lag (yes, lag is actually the correct term, both for connection delay as well as hardware delay) is about the same, there's not many NPCs in Upper Jeuno in the area where most Bazaars are these days (and there's more NPCs outside now as well).
As for lagging the zone out for people passing through, what is there in Upper Jeuno that people need to do? The only problem I see with this is in Port Jeuno (and possibly Ru'Lude Gardens), but there's not nearly as many bazaars in either of these zones as people claim here. And even without any Bazaars Jeuno would be laggy as hell because people are lonely and love standing next to Horst and Joachim and pretend they're their friends.