Thanks for your support my brother...or sister. And I've seen a great many shows like avatar and one thing I know is when Aang Iroh and the others reach Ba Seng Sai they'll spend most of the??remainder of the series there. For these reasons.
1. The creatures need you to feel a bound with the city when it is eventually attacked by the FN.
2. Since Iroh is going to be in the city Aang won't have to leave it to find a Firebending teacher.
3. Iroh' sconnection??and past with the city will eventually lead him to defend it against the FN doing so will make his??character's story come full circle.
4. The more I think of it the more I think that Ozai will actually be on the cite of the invasion of the city. since it has never made much sense to have two separate story arcs (Aang fighting the Fire Lord and the rest protecting the city) that way both can happen in the same place and time being more fluid.