I think to speak of an anime "deserving" a dub is to put the emphasis on the wrong thing. The appropriateness of an anime for dubbing is not a function of its quality but of many other factors.
Let's take two examples: Baccano and Gintama. Baccano has been dubbed, Gintama has not.
As a period piece set in 1930's America, Baccano greatly benefits from a relatively high-quality English dub track. Hearing the Japanese language coming out of the mouths of what are obviously American characters from a very specific time and place is just plain WEIRD to an American audience. It introduces an artificial barrier between the viewer and the setting and weakens the impact of the gangster motif. That's not to say that viewers don't have every right to watch it subbed if they feel the benefits of subs outweigh that drawback, but I'm very glad that the dub option is there.
One of the well-known drawbacks of dubs is that the need to time the lines to the lip flaps makes the job of translation more difficult. In Gintama, the translation is ALREADY extremely difficult due to so much of the humor relying on Japanese puns and pop culture references, many of which are explained by lengthy translators' notes (depending on which version of the subs you're watching). Despite the crazy setting, the characters are clearly meant to be speaking Japanese most of the time, so the objection raised above doesn't apply. The last thing it neeRAB is for the translators to have to deal with arbitrary limitations on how they may translate. And more importantly, since it's such a niche title, there's no monetary incentive to dub: a dub track would almost certainly cost more money to produce than it would bring in by attracting new viewers. So Gintama has no dub, and rightly so.
Does that means that Baccano is more "deserving" of a dub track than Gintama, that the presence or absence of a dub reflects well or poorly on their relative quality? Of course not. It simply means that in Baccano's case, the benefits outweigh the drawbacks, and Gintama's they don't. Different situations call for different approaches.
When it comes to the larger dub-vs.-sub debate, I think going to either extreme, only watching subs to the exclusion of dubs or vice-versa, is a bit narrow-minded. All else being equal, I tend to prefer dubs, but there are plenty of exceptions (I much prefer Death Note subbed, not because the dub is bad, but because the Japanese setting and characters are such an integral part of the story), and if I like an anime enough to watch it multiple times I will always watch the subbed version at least once to appreciate the subtle differences in translation. I know other people who, all else being equal, tend to prefer subs, but are willing to make exceptions as well, and I respect that. What I find harder to sympathize with are those who ONLY watch one or the other. Why limit yourself?
This has been said, but deserves to be emphasized: the original version is the version with spoken Japanese dialogue and no subtitles. The act of translation, in and of itself, alters the original. The act of reading subtitles, of having to divide one's attention between scanning the lines at the bottom of the screen and watching the action as a whole across the entire screen, alters the experience of the original. And, of course, replacing the Japanese spoken dialogue with spoken dialogue in another language, spoken by different voice actors, alters the original as well.
Therefore, the only people who can claim to be watching the "original" are those who fluently understand spoken Japanese and can watch with no subtitles OR dub track. There are plenty of legitimate reasons to watch a sub track, but it being "the original" is not one of them. Both methoRAB of viewing have advantages and disadvantages when it comes to getting a viewing experience that closely approximates the original.
As for whether the sub option "matters," obviously it does, or it wouldn't be included on DVD releases at all. It's one legitimate option among several. I'd count that as "mattering."
Weakened, but not eradicated. No matter how small relative to the rest of the picture the subtitles become, there's still the matter of the viewer's attention being divided between viewing the action and scanning the subtitles at the bottom of the screen. Since anime is primarily a visual medium, the impact of this should not be minimized.
