Anime is such a big industry in Japan and because of this the voice acting industry must be taken very seriously and must produce a lot of very capable people who can produce very animated, emotional/less, individual characters with their voice. However in dubs, it sounds as though, for an example, they heard the bad guy had a deep voice so they pick a guy with a deep voice, HOWEVER he can't convey the character or produce the character's emotions in delivery. Now it's not to say that the individuals at fault because he/she is unable to perform on par with that of the original voice acting, rather it's the lack of the industry and competition in US/AU/UK/etc that produces lower grade voice actors for dubbing anime.
Now I love watching anime and I dislike watching it dubbed for many reasons. It’s mainly the quality of delivery, and what that quality brings to the anime. In anime emotions, actions, characters are often exaggerated. Whether it be an exaggeration of being energetic, arrogant, spaced, quiet, nerdy, strong, week, etc, these qualities come from the animation but must also come from the voice as well in order to make it worthwhile, otherwise the emotions aren't there to be received. An example of how ridiculously bad dubbing can be is a part in Suzumiya Haruhi no Yuuutsu that I saw. (I’ve only seen this part cause I came across it as a dubbed vs subbed video ^^) It’s the part in ep10 where Kyon’s classmate tries to kill him to see if there’s a reaction and Yuki enters, and they have a battle. It’s almost laughable at how bad the dubbing is in comparison to the original.