One might argue that NWN would be better if (and only if) you had explored all of the multiplayer options. With NWN you can create your own campaings and play with friends over the net. Its more like having a D&D group than BG games will ever be.
Having said that, you can still quest in the BG games (I include Ice Wind Dale series) with friends online or at a lan party. So I completly agree with sashton. Have you ever played through BG2 with a group of friends in the same room where you can talk? It's great fun. "Death is lighter than a feather, duty, heavier than a mountain."
Plus, the folks over at TeamBG created all the tools necessary to create (well, actually it's more like Cut and Paste) your own campaigns in the BG series. And I *liked* multiple NPC's in the party and their interaction - but it must have been a real bugger coming up with the various NPC-NPC interactions that made them so entertaining. I admit I wouldn't have the patience to script all that.
The BG method of getting tired (and unlucky) *could* have been used, and even expanded into hunger and thirst. The Diablo method for combining weight and bulk of inventory was a good idea - although it still feels like playing Tetris.
I *am* a little dismayed to find that as a level 1 Rogue I can use Magic. BG had a good idea giving Rogues the "McGuyver" (use-anything) ability at higher levels, but at level ONE??? And I'm not certain if this is a bug but when I purchased a Monk-only pair of gauntlets I was permitted to wear them - and receive the +1 electricity bonus when fighting barehanded. Maybe the NWN McGuyver skill extends to other than Magic?