Also, realize that this was the originally intended publishing order. When unexpected Real Life Events delayed the release of Unity, TLHoD was pushed up to fill in the gap in the schedule.
I have never heard this before. In fact, I seem to recall reading in Voyages of the Imagination
that The Left Hand of Destiny
delayed for quite some time by J.G. Hertzler having trouble putting everything together, leading Marco to bring Jeffrey Lang to the party as co-writer. So I'm a bit skeptical of that.
And so far as I know, Marco always said that publication order was his intended reading order as editor.