Well, as anyone could tell you I don't "post and run," but right now I'm limited on time--getting ready for a 9 week block of Greek 102 starting Monday. But I will say this: any linguist or translator knows that a translation can never be as accurate as the original. For you or the guy in the video to prove that the LXX translation is closer to the originals than the Masoretic, you would have to prove that the Hebrew text underlying the LXX was closer to the originals, and no one has been able to do that.
Furthermore, it is common knowledge among scholars that the LXX is widely divergent in its renderings. There are very literal renderings and also very free renderings. So to make the statement that the LXX is closer to the originals than the Masoretic begs the question: which part of the LXX?
So in a lot of places the Here is a quote a bout that from famed scholar Fredric Kenyon: "It is maintained that the Greek translators were not always good Hebrew scholars, that they often made mistakes in translation, and in other respects took liberties with their text"(The Text of the Greek Bible
The basic premise that the Greek translation is better than the original Hebrew shows ignorance of basic translation theory, the textual criticism of the OT, linguistics, etc.
Here is a specific error. At about 4:20 he says something like, "The Masoretic text is not the Hebrew text, but is a copy." Well, duh! That's all any Hebrew or LXX manuscript of the OT is. We don't have the originals of either the Hebrew or Greek OT. This to me shows ignorance of the entire issue of the transmission of the various texts--textual criticism if you will.
He said there that the LXX was translated in 250 BC. That is highly questionable. It actually was not a single translation, but put together from various translators in various years. So you can't say that it was translated in one specific year.