Ickorus said:
I want Black Marsh purely because it's the racial homeland of all my TES characters.
Pretty much this, but there are other reasons too. Black Marsh would actually be a really good place to set the game in.
It has 8 different and varied cities (judging by the admittedly brief descriptions available in earlier games at least).
The Argonians are organised in a clan-type / tribal culture and government.
They have a long standing hate for Elves, and especially Dunmer (no TES game would be complete without tons of racism).
Instead of roads the main form of transport is by rivers and water ways.
It's a "a lush and threatening land teeming with poisonous plants and violent predators".
It has sentient chaos-worshipping trees that share a symbiotic relationship with the native-Argonians.
What's not to like?