I think the voice acting just needs the right mind set. It's supposed to be vaguely reminiscent of middle ages English. And your character is supposed to be a "rogue".
There are a lot of downsides to Two Worlds, like corpses that never disappear (I feel like my character is single handedly destroying all animals in the kingdom), mute enemies, odd looking necromancers, poor magic system, etc.
But it did have an amazingly large and diverse world to explore. And some very nice side quests.
It's not Oblivion or Morrowind or Fallout quality. Maybe it's not quite "amazing" but Two Worlds is under-rated, in my opinion. I would get Two Worlds II but it looks like it's never going to be released for the PC.
I must admit I didn't recall some of those flaws, especially the non-disappearing bodies. I do remember that the necromancers were a little odd, but that was part of the game's charm! And they were suddenly less amusing when you found yourself beset by a whole bunch of them and their minions...
Things I particularly liked were the large, varied and intelligently put together world, whether exploring the wilderness or the contrast between the different cities. I especially enjoyed the Japanese-esque city in the south-west with its modern Harold Faltermeyer(?)-composed incidental music because of the way it just had such a different vibe to the more traditionally European-type mediaeval cities elsewhere. Other elements like the way weapons and armour could be combined to give better quality versions of each were also a nice touch.
I think really, the only thing that let it down for me was that the MQ was sometimes a bit iffy, and elements like cutscenes were rather badly done. But considering it's often viewed as a laughing stock, it has a lot of elements that put more respected games to shame. And at risk of joining the "not as good as it used to be" crowd, it's a shame that TW2 seemed to lose something of the magic of the original: it was more professionally done in many regards, but it lost its way somewhere.