I wouldn't consider the removal of parts of God's Word "petty".
Even if we wish to entertain the fiction that the LXX were a good (or even passable) translation, the fact remains that the apocryphal books were added to it well into the Christian era. They were not part of the Jewish canon, and in fact, most of these books did not even exist when the original (as opposed to the much later redacted) LXX was translated. Did you know, for instance, that Baruch wasn't even written until around 70 AD, or that the Wisdom of Solomon was produced at some point between 75 BC and 40 AD? Even other books like Susanna and Tobit were produced in the century prior to Christ - and were not included in the original production of the LXX between 250-200 BC.