There is a lot of discussion in this and last month's
Opera magazine about the decision of both ENO and the
Opera Theatre of St. Louis, both advocates of Opera in English, to use surtitles for their performances. The comments include reasoned arguments by a noted singer (Andrew Shore) in the letters, to snide asides in unrelated reviews ("Now that even Saint Louis, like ENO, has surrendered to the congentially lazy and introduced condoms..."). It is certainly a hot topic among the writers and readers of that august publication.
I've always had an ambivalent feeling about both Opera in English and surtitles. I studied at Indiana University where we always did operas in English. At the time I felt it was a disservice to the students, since most companies in the "real" world perform in the original language. As a concept, I like the idea of opera in English. I think it would certainly be a more complete experience for the audience if they could understand and relate to the text being sung. But the reality is more complex. First, at least in the US, the translations used tend to be trite, without literary merit on their own part, and secondly, no matter how hard a singer tries, some text will never be understandable, because of the vowel modifications required within certain tessitura.
On the other hand, surtitles have their pitfalls as well. I've been at performances where ill-chosen, or ill-timed translations have caused audience guffaws in the most dramatic moments, and the physical limitations of looking above the stage and then back down to the artists, interfere with my personal enjoyment of an opera. The Metropolitan Opera solution seems best of all, since the translation is closer to an audience member's typical field of vision, titles can be turned off if they are not needed and most (although not all) neighboring screens don't interfere.
The argument that surtitles make singers lazy and less concerned with their diction is total hogwash as far as I'm concerned. I was a professional singer for 10 years and have many friends active within the industry and I can tell you that I do not know one singer who has ever given any consideration to whether or not there were surtitles in forming their approach to a piece. Technique is technique and surtitles would never change that. If a singer's diction is going to be bad, it will be bad, and the presence (or lack of) titles certainly won't have any effect.
On the whole I think that titles are good for people new to opera but I do question the wisdom of using them in performances in the audience's native tongue. I'd prefer that they weren't there, but on the other hand they are usually easy enough to ignore. So I'm not really sure what the ruckus is about.