"The only appeal that I can see Morrowind having is to the Diablo-generation..."
You're comparing Morrowind to Diablo!? Everything about NWN screams Diablo. It even had the "original dialogue" you seem to prize. Too bad there are so few characters to interact with. NWN is a typical example of what not to do in an RPG. Try playing it more than once. "Is it time for the explosion and break in yet? Oh...here it comes..." Yay! Here comes Chapter 2! Luckily, they've "unlocked" the camera so now you can see your character from any perspective--any perspective, that is, but the character's own. You can't even swim in NWN. Even Quake is more immersive.
I have played Fallout, btw. It's a fun game--but it's not the same type of game. Sorry. And if it's mods you want, try http://www.rpgplanet.com/morrowind