@whiteoctave, thank you. I’m jealous about your Allen books!
Really interesting. I would like to know the unwritten ideas of some geniusses like Allen. I’m a big fan of Allen and Sturtevant too. But no, I’m not really jealous, I’m rather happy for you and remember we are friends! 
@Dionysius: I agree with most of it. It’s correct as you say it. But I think and I think you think so too that it’s verry important in a language to have a standard pronunciation.
I know a Latin anecdote about that. Some time ago the world spoke Latin as we know. And as it is now, when we try to speak Latin, every person who tries to speak Latin has his own tongue, his own accent in it. Lipsius tells us that it happend that poolish people spoke Latin to Frensh people, and that these Frensh people asked to speak Latin, cause they didn’t know poolish. The poolish people spoke Latin but as their own language and the consequence was that the Frensh didn’t understant it, they thought it was poolish.
With Greek and Latin this is less important, cause mostly we write them. Although sometimes the languages are spoken, and then it’s important to understand each other. Therefore I think we have to do our best to have a standard pronunciation. But THE standard pronunciation does not exist. We will never be able to make dissapear our accents totally.
But there are a few things we know! When Herodotos describes the sound of a goat with beta-eta, it’s very unlikely that the goats in Herodotos’ time made a sound as ‘phi’ (as it is pronounced in modern Greek). With these onomatopies we can restitute the sound of the ancient Greek letters. There are a few other aids too. But I know you know them, they are in Allen, Sturtevant, …
It’s true that we don’t know native speakers, but that’s not a reason that we wouldn’t be able to restitute their ‘standard’ Greek.
And if we are able, and I really think so, to be understood by an ancient Greek (what’s not really possible, I know), hypothetically spoken off course, then I think we have to be proud of our pronunciation, even if it’s not as good as that of a Plato.
Secondly, Greek is a language wherein the dialects are more important than in any other language. And as you say, there must have been differences between these dialects. So I think almost every polis had her own ‘standard’ language. Later we had the koine as a standard language of course, but that’s not really classic Greek as we mostly see that.
So I think we agree?
Surely wause we are correct!
Greetz,
Moerus.