I actually agree with the complains about the English voice dialog. The issues aren't the individual lines but how dialog selection and subsequent chain of speech is disproportionally variant. The characters can be speaking in one tone in one moment and in a completely different tone 10 seconds later. There is no ramp up in inclination and none of the dialog choices presents a completely fluid listening experience. It appears the ADR work was simply done 1-shot off a dry script. And even if it wasn't, the presentation makes it seem that way. That said, I do recognize a few popular name in the industry so the English cast is fairly good.

There are ways to actually blend dialog without multiple full ADR sessions. However, D2 appears much more focused on game, than tech so I don't expect any of those techniques to be employed.