As far as I can tell, the positive qualities that Ellison could bring to the table (sales skills, toughness) are ones that Musk largely already has, and, what's more worrying, it seems likely that Ellison will enable the character flaws in Musk that the two share (hyperbole, unscrupulousness).

Meanwhile, Ellison adds nothing I can see in terms of manufacturing and and little in terms of adult leadership.

I would argue that the ideal director in terms of complementary skills would be somebody like Tim Cook (even though Tim himself would probably be too likely to have conflicts of interest to serve).