The English voice actors being terrible is only your opinion. Many of the voice actors from DBZ are great with dubs. Sure, they were much weaker in their DBZ roles, but that's only because most of them got there start there. Even then, there actual voicing of the character was not bad, for the most part. Trust me, I've seen far worse dubs (and yes, I'm sure that you know all to well that there are other DBZ dubs that have even far worse voice acting than any of the voice actors from the FUNimation or Ocean dub of DBZ).
Also, it is kind of hypocritical of you to just say that the voices aren't good for any of the characters (and once again, I only mean the voices, in terms of their tones, not in terms of the actual English script) in the dub, while criticizing anyone who doesn't really like the sub voices.
Oh, and as for the acting being too "cartoony," I think that you are forgetting that DBZ is essentially a cartoon (and yes, I do consider anime to be cartoons from Japan).
I'm not quite sure what is so realistic about DBZ's sub at all. I mean, I don't speak Japanese, but I'm willing to bet that Japanese people don't sound like the characters in anime in their normal speech (in regarRAB to seeing video interviews with mangaka, seiyuu, etc.). I mean, sure, it may seem more believable, if that's the term which you want to use, but I just can't see it as being realistic, since normal people wouldn't talk like an anime character in their normal speech, no matter what country that they are from. To give a better example, I would compare how American people normally talk, to how people talk in Hollywood movies. Sure, their speech and acting might be more "believable," but there is a difference between that and realistic, since actors are trained to have distinct voices for different characters, but make those voices work out well, and be easy for an entire audience to comprehend. If you compare the way that you, frienRAB, family, or other people that you know speak, to the ways actors in movies speak, then the difference is clear.
So, basically, there is no "realism" in acting or voice acting in entertainment. There is just good, mediocre, and bad acting, and if the dub voice acting is bad to you, in DBZ, then that's fine, but just because you feel that way, doesn't mean that its a fact. Other people like it, as you can see, and even people like me still enjoy the dub to some extend. And, BTW, just for the record, in case you try to say that I am being bias towarRAB the sub, I would just like to remind you that I voted for the sub, and even stated that I would pick the sub, if I had to choose, in an earlier post.
BTW, I agree with macattack. The universal version of an anime is what you deem it to be. Actually, scratch that. There is no unviersal version of an anime, because different people will always have different opinions on dubs and subs. And, subs are not always better than dubs, for everyone, despite you feeling that way. I can say for sure that the dubs for Rurouni Kenshin, Yu Yu Hakusho, Death Note, Cowboy Bebop, and various other series, were more enjoyable for me, personally, and many others, than the subbed versions of those anime (even though I did enjoy the subbed versions for each of those, very much, as well).