to me it seems very... empty. Some torches on the walls would lighten it up, while retaining the dark mood. With these kind of things, I'm used to seeing a large central room, just to give the map some focus. Perhaps it could be a meeting place for some secret society made up of patrons/ innkeeper etc. , or a cellar where the ale is kept in secrecy.

but if you cant change the layout of the tunnels, then the torches would be a nice addition.