Poor design, terrible camera control, bug-ridden AI, and awful models/textures for its high-end system requirements...
Though it may sound harsh, I am in agreement with a lot of people who gave this game a similarly low score. It falls woefully below even the most mediocre of game standards.
In specific:
• Difficult camera implementation: The default camera settings work counterintuitively to every game that falls within the same general category. This is further compounded by having to switch between three different "view modes" where one is more than plenty.
• Bad AI: In dungeons characters in your party often get lost, freeze in place, refuse to help when under attack, and sometimes fail to follow the leading character altogether. There have been patches and even a couple of expansions, but none of this was ever addressed or fixed for some reason. It's ridiculous that players are expected to actually use the pause function in the middle of battle just to work around it when the developers can just as easily fix it.
• Substandard graphics with higher-end video card demands: No efficient method of streamlining the games graphical engine or reducing needless elements of rendering were ever employed.
Bad models and textures. (Even with anti-aliasing and using other video setting features designed to improve them)
Let's use a game like World of Warcraft for example. It' has extraordinarily low system requirements but is graphically lush and complete, featuring many fine customization settings for video. So there is absolutely NO reason why a game that has higher hardware demands than WoW look much, much worse than it does.
• Needlessly verbose and corny dialogue coupled with painfully bad and often pretentious voice acting (minor gripe): The voice actors in this game are god-awful and usually abrasive to even listen to.
None of the VA matches the emotional context of the fundamental script and is incredibly obtuse when characters speak with one another in cut-scenes.
I found myself muting the sound every time a githyanki or lizardman even opened his mouth. These monster voices in particular come across as VERY cheesy and remind me a great deal of how black metal singers and pro wrestlers sound. (i.e. childishly goofy.)
Overall:
Eventhough 3.5 D&D is no longer around and that Forgotten Realms is a very rich and immersive world, this game does the franchise no favors.
If you genuinely enjoy D&D, RPGs, and even just good games in general, do yourself a huge favor and skip this one. It's nothing but crap, through-and-through.