Just Locus, like others have said, the camera and party controls were quite clunky and frustrating. Not quite as terrible as BG3's today, but still pretty all-around bad. Check
my guide for some pointers to ease the pain.
The OC was also a disappointing experience, generally underwhelming in spite of one or two standout moments (the trial, the keep) and riddled with rushed, poor implementations. That said, NWN's own OC was widely panned and for good reason, yet it didn't stop the game from pulling strong with subsequent expansion content and a huge library of fan modules.
Which brings us to NWN2's biggest failure - the Electron Toolset. The original NWN was built as a platform first and a videogame second, and that's reflected in the magnificent Aurora Toolset, powerful, reliable and supremely accessible. Module-building was as much a feature of the game as singleplayer and multiplayer. NWN2, however, was developed as a regular videogame, with the dev tools offered "as-is" to sweeten the deal. Electron, despite
some improved building capabilities, is a massive regression in usability due to labour requirements, poor design and brittle coding. You still
can build whole campaigns with it and some people have, but few had the patience for it and NWN2's community library is a fraction of NWN's as a result. So NWN2 got its good expansions (SoZ, MoW and the stellar MotB), but not as much fan content.
To add to this, NWN2 did somewhat abrogate the multiplayer/co-op focus of its predecessor. This was somewhat logical since NWN also zeroed back into the singleplayer side after the OC and the bulk of community content was singleplayer, but the PW community was a sizeable and persitent driver in the game's modding scene. NWN2 couldn't tap into that to add to its longevity.
Also, as a minor point, NWN2 was actually a bit demanding on hardware when it came out. I couldn't comfortably play it on release and had to wait to upgrade my PC. Not the be-all, end-all of anything, but it certainly won't have helped early adoption.
P.S.
catfood, fuck you too, buddy!