Is dynamic equivalent translation acceptable?

While researching the ESV translation before deciding on a new Bible, I can across an article by Leland Ryken attacking the notion of "dynamic equivalence". The KJV and versions that share it's heritage insist on word-for-word translations. Apparently the committee that translated the King James Version coined words in English so that they could provide an equivalent to the original Greek and Hebrew terms. In contrast, dynamic equivalent translations concern themselves with translating the meaning of the original texts into language that can be understood without special religious or historical knowledge.

One example the article uses is John 6:27 which says the Father set His seal on the Son of Man. Now to a modern reader, the idea of setting a seal on a person will likely be obscure since we no longer rely on seals as a form of authentication, protection and preservation of documents. To make matters worse, it isn't entirely clear what point Jesus intends to convey, since the context of the passage is food, not a document. So translators have a range of less-than-ideal options:

1. Leave the obscure reference obscure.
   
2. Add words in English the explain the function of a seal in this context.
   
3. Substitute a modern equivalent concept that gets across the meaning of the original Greek.
   

A literal translation has little choice but to use option #1. The majority of modern translations seem to prefer option #2: "seal of approval" or "seal of authority". And, of course, paraphrased translations chose option #3: "guaranteed", "sent for that purpose", etc. As you can see, the further down the list you go, the more choices the translator has available, but the fewer choices left open to the reader. By the time you get to option #3, there are any number of ways to express the idea, but the reader has no access to the other possible connotations of the word "seal" since the word itself has been removed by the translator.

For Bible study, there can be no question that an dynamic equivalent translation will not serve. The important questions a text raises are often answered or strongly influenced by the translators. If the text reads, "seal of approval", it will be difficult to interpret it as a "seal of protection" no matter what other evidence may exist.

But I think it's somewhat naive to assume a literal translation is the most direct communication of the original text. In this instance, the original Greek and Jewish audience would have had no difficulty with the image of a seal and what it represents. The more troubling image would be Jesus claiming to be the "bread of life" a few moments later. In fact we know this image was intended to clarify Jesus' status with the Father not obscure it. The paraphrase used by The Message, "He and what he does are guaranteed by God the Father to last", has a strong appeal in that light. The literal translation needlessly obscures what ought to be an obvious interpretation.

Now there is a danger to accepting dynamic equivalence, but the danger isn't we will have too many texts (become "destabilized"), but that we will have too few. For the last 20 years or so, the churches I've attended have been saturated with the NIV translation. It's an extremely good translation, in my opinion, but we have suffered because it has held a monopoly on English understanding of the Bible. Before the NIV came along, I believe we were in no better shape since the KJV and its descendants were dominant. Rather than being over-interpretive, the Bible was seen as overly-obscure and difficult. In both cases, the best response is to use a variety of translations for a variety of purposes so that translation difficulties of one can be corrected by others.