I am not sure if this has ever been discussed or even looked at, but it I think there might be some merit in the PrC Pack (
http://nwnprc.netgamers.co.uk/manual/index.html).
I have used this in several single player mods and it adds a ton of things to the game. First off are many many Prestige Classes, many of which would probably not be allowed. The Shifter class, however, is much much better and closer to the PnP version which holds high appeal with me.
Also included is a spell pack which both adds numerous spells and changes many existing spells to be closer to PnP.
And lastly are several new feats that are helpful and should have been included in the game IMO.
Anyway, like I said, it may be more trouble then it is worth. But it might be worth more then the trouble.
Just a thought.
Thanks.