Who should of thought NV should of had Metro tunnels... instead they have sewers

You're really fixated Fallout 3 aren't you? I didn't mind FNV having sewers instead of the metro, and the metro, for me, got boring after a while.

I wouldn't mind a more complex underground system for New Vegas. It certainly would help with exploration.

I also like the area around New Vegas (the city area) to be much more cluttered with abandoned buildings and ghettos like Freeside.