I've tried learning languages before; it doesn't work for me.
One of my teachers used to say : "Learning a language isn't hard. It's not like math, where you can be awfully bad because you don't do it naturally. You already learned a language since you speak one. So get to work and stop complaning" (that last part was part of the quote, it's not directed at you). But you're lucky, you already speak English.
sub snobs sometimes prefer subs because they sometimes understand the language, prefer to listen to the original performance and the original writing and just need some help at times with the vocabulary.
Anyway, the problem with good dubs is that :
A-They are extremely rare
B-A lot of subtle tones, words, and expressions are language-specific. For exemple, there is no way to translate in french "Get over yourself!" properly. What you mean with that expression, with the tone you usually use, can't be meant using that language. There are even some concepts that don't exist in some language. "Exposition" as a writting technique is a concept that doesn't exist en french. (And there are other exemples the other way around). So the translation often has to use clever tricks to keep the meaning as close as possible to the original work. Granted, subtitles don't help with that, but hearing and understanding the language directly surely does.
C- Something that sounds good in a language can sound terrible in another and vice-versa, because the culture is different. Plus, you can't translate language habits or accents.
Take the original performance in Letters from Iwo Jima (I don't understand Japanese, by the way). The characters have very specific ways to speak when they acknoledge orders or speak to a superior, that are part of the Japenese military tradition and culture (at least, I guess that the film got that right). Even though I don't understand directly what the characters say, I am able to get a sense of the differences between the US and Japenese soldiers, between the two cultures. Use dubbing and put a "Sir, yes, Sir !" in there and everything is lost. You can try to mimic the way a foreign language is spoken using your own, but it doesn't work very well.
That one might come as a surprise to anyone reading this in nations like France, where native-language dubbing is the norm: Americans are huge snobs about dubbing now - even kung-fu movies play subtitled here.
Hey ! Nice, thanks for thinking about your french readers !
By the way, native-language dubbing got a kick in the balls in France in recent years since people in charge have finally figured out that it helped us being rubbish in English. A lot of theatres play both dubbed and subtitled versions of movies, over here, now.