PW or PF are like Napoleonics Wars; 200 players can play in real time on a same server. And it's all. Certainly, PW and PF have some features like automatic respawn and money system who differs a lot of NW, but according me, these two mods are not open world mods, but more persitent mods (there is a huge difference).
NWC is technically the first
real open world mod in Warband. NWC makes finally the server linking possible on Mount & Blade: Warband. This really is a giant progress on the game! When PF or PW will offer a travel system between few server or a another system to creat a real immersive world (not only a server of 200 slots with a limited map), that would be a open world.
To return to the main subject, thank you for the feedback!