For many people Morthal is an undesirable place. A place where the youth leave the moment they are able to. Its dangerous location next to a swamp filled with monsters certainly doesn't help. For others Morthal is a idyllic place far removed from the dangers and worries of the world. A small town in the middle of nowhere. Whatever the people of Skyrim may think the Morthal we see in the game is... dissapointing. It is still supposed to be the hold capital and largest city of Hjaalmarch. It doesn't even have any defenses! Riverwood, a town founded mere generations ago, has better defenses than the capital of Hjaalmarch.
The Great City of Morthal tries to remedy this. It adds gates, watchtowers and a stockade around the city and a unique bridge. It also adds detailing around Morthal to try to make the city feel more lived in. It tries to keep that small town feel, Morthal is still one of the smallest of the hold capitals afterall, but at the same time make it feel more city-like. The Great City of Morthal tries to close the major gap between major and minor hold capitals just to the point that it all makes a bit more sense and adds that tiny tad of immersion. This mod doesn't add houses or NPC's.
This mod is not compatible with any mod that significantly alters the area surrounding Morthal. Interiors are left unaltered.