I see only three reasons on why a remake of NWN (I'd rather avoid a sequel, since nowadays what we'd get would most likely be a weird hybrid of NWN with Neverwinter, containing intrusive DRM and micro-transactions).
1) Making it popular once more - a new title would draw many more players than any possible (unofficial) revamp of the original game. This game needs advertising, but this alone won't do the trick - most prospective players would not be interested in trying it out given its age, but it's a different story if it's a modern remake.
2) Improving its graphics - this is somehow related to my previous point, but I think all of us would appreciate some better graphics for this game, not just the new players.
3) Lifting hardcoded limitations - I think that's the least important reason, but it would still be very appreciated.
On the other hand, what level of compatibility with old NWN content should we expect? If there was zero compatibility, like was the case with NWN2 (besides NWScript), then we'll have to reinvent the wheel, which is not exactly desirable. On the other hand, it would be impossible to allow full compatibility, given the differences in quality between content made for the original game (like tilesets and models) and the remake.
I think this compatibility should encompass all official content. All original creature models, tilesets, skyboxes, everything. This should also extend to content added in patches, including horses, Infinite Dungeons Halaster model, etc. This would certainly be difficult, but achievable - and would at least allow to play all the old hak-free modules out of the box. That's a level of compatibility that, I think, would be a reasonable middle-ground.
Then I'd want the game to provide fixes for bugs still present in the 1.69... though pretty much all of the important ones have been fixed by Shadooow's patch by now.
That's a lot to ask for and that's why I think it won't happen. Not in a way that I, and probably many others, would find satisfying.
I think the real question to ask is - is there any way to bring an influx of new players to the community (and make them stay longer) assuming no NWN remake/sequel will ever be made?