Probably the three main reasons why NWN2 rated poorly compared to NWN were:

1) Much smaller developer so it got pushed out a bit earlier, resulting in quite a lot of bugs early on (most since fixed).

2) NWN2 just seemed to be really hard to get to run well no matter what your system specs were. Were constant reports and issues with folks having trouble with slowdown and stuttering ingame (didn't have the issue myself, but I had a very old system at the time and just ran it on all minimum settings)

3) Most importantly for the general multiplayer community, NWN2 toolset was a LOT more complicated and difficult to use initially than the NWN1 toolset. More powerful, but not at all user friendly unless you're willing to take the time to learn how it worked. This meant that community content took a lot longer to start coming out with the same (relative to NWN) level of quality, or even quantity.

4) Servers had to be much smaller due to the way the game handled resources. While you could have massive sprawling worlds in NWN1, going over a certain number of external areas would start causing problems for the server (no longer such an issue).

To sum up: buggier on release, performance issues, much less community content, smaller worlds.

Most of that no longer applies.

Haha, you silly goose, you said three reasons and then listed 4. I have nothing to add except that that made me laugh. :P