Temple Of Elemental Evil isn't remembered that fondly because it was a simple dungeon crawl based on a really old tabletop campaign, and its encounter design was so-so (the endless waves of bugbears in the titular temple, etc.). It was also written by Tim Cain, a mainly programmer who's admitted to sucking at writing since. The mechanical foundations for a great game have been there, but mechanics purely can only take you so far. It's like having great weapon mechanics in a shooter game but then not the level and encounter content to let them shine. Maybe a follow-up project, one in which Troika could have focused on the content rather than the engine, would have fared better.
I've personally never played Hordes Of The Underdark, because the main campaign of NWN was even more lacklustre. It's the worst thing of Bioware I've ever played. It was clearly an afterthought/demo of what the toolset would be capable of at best, which is where the main ressources were spent. After BG, that was a big blow to somebody who expected anything roughly onpar. Maybe I should give it a try, I've heard good things about it. I'm not a graphics whore, but admittedly I nowadays unlike BG find it hard/er to get back into NWN in parts because visually it has aged terribly (development that started back in the 90s took really long and was low poly even for its day). Doesn't help that its art direction had always been lacklustre and everything is tile-based same, same looking due to the requirements of the toolset.
