I've been playing this quite a bit since I got it. And so far, I do like it quite a bit. It might not have the incredible depth of story and awesome story that Mask had going on, but Storm's story is still good, so far.
Since you create a WHOLE party (of four) from scratch, which gives it that Icewind Dale feeling, you might not have the level of interaction and banter from party members as any of the other NWN's. But now in dialogues with NPC's, any party member can now talk into the mix (instead of just your lead member) -- and you can do the talking as any party member. Based on your skills, stats, and whatnot -- certain party members might get extra dialogue options when talking with NPC's. Along with your party of four that you create, you can have ONE extra in-game "cohort" join you (that Obsidian made, that you can find in the gameworld) -- to get a party of five going, which you will also have full control over.
At inns, you can create party members and swap out party members and whatnot, as you see fit. Very cool.
I really miss the cinematic style talks w/ NPC's were handled -- as that is gone here, for some reason; even with the more important NPC talks that are still voice-acted, it's not done cinematic-like. It basically goes back to the old NWN style -- since probably some of the game is voice-acted and some isn't. Seems odd for it to have gone this way, but it still is fine and all. So far, yes -- the voice-acting is pretty good from NPC's that actually have voice-overs.
Overland map is...interesting. You traverse the map Fallout 1 + 2 style, basically -- where you click and point where you want to go. This world feels quite open to explore -- as you can explore the map to unlock locations. Based on your skills and stats, you might find extra areas, extra items to take, etc etc while on the map. Also based on stats, you might see enemies from further away and be able to dodge running into them. If you run into enemies, depending on who and what they are, you might be able to bribe them away, evade them completely, or fight them -- up to you. It's best to also have a ranger in your party, as they are pretty much necessary to be able to avoid battles.
Technically, the game performs even better than it did before -- and it looks much better now, since you can run it with WAY more graphical bells and whistles turned on.
So far, I'm liking this.
From what I've played so far, I hope it's true and Obsidian does do another NWN2 Expansion -- and can use this as a template for their next campaign and expand upon it. I hope their next campaign, it's more epic-level based, though. If you start Storm of Zehir fresh with a new character, you will be jumped up to Level 5 and you can spend the points as you see fit, of course.