...and his stated intent to explore mythology, and his referring to Olaf Stapledon...
To which reference are you referring?
He referenced Stapledon's FIRST AND LAST MEN specifically, but whether it was in STARLOG (he was interviewed somewhere between issue 15 and 22 I think) or somewhere else, I'm not sure. Is it possibly contained in Gross' TREK THE LOST YEARS?
He barely mentioned TREK in his original BODY SNATCHERS commentary, does anybody know if he did a new commentary for the newest version of the movie on dvd?
EDIT ADDON LEANDER, I think the similarities have to do with Probert being something of a protege of McQuarrie, and he certainly saw Ralph's art a few times before coming onto TMP, let alone TNG.