lol, NWN never would have been made without WotC's strict permission. If NWN's FAQ says it's ok to create mods from old games then it is. Bioware isn't stupid enough to bite the hand that fed them like that. You really don't think Bioware would have brought this issue up previously with WotC? It's in the FAQ which means Bioware's already asked WotC about it and WotC has responded thus. Heck they probably already had that issue covered before NWN even began development. Otherwise WotC would take one look at the NWN FAQ and sue Bioware's pants off.
Not to mention as Maerdwyn already pointed out, people have already been posting such things on the official NWN boards. If this were illeagal as has been implied here, WotC would be obligated to prosicute not only those posters of the illeagal material but also the owners of the site that allowed them to post it. And since it's the official NWN site owned by Bioware, I think it's safe to say that they wouldn't want a law suit and jail time on their hands before the game is even released.