Michael Abbott gives a wide range of reasons - derivative stories, poorly conceived and stereotyped characters, insipid dialogue, and most importantly how miser are game developers about being creative with voice. Michael writes,

It's not about being creative. There's no time for that. It's about recording cues. We call ourselves actors, but we're really technicians. There's very little space for spontaneity or imagination in that room. The people I've worked with have been very nice for the most part, but if they could replace me with a robot that can emote in ten different dialects, they would do it in a second.