John Milius' Conan was great in of itself.
His brain (and the he really does have a brain) is a giant meatball of testosterone, bordering on the sort of archetypes sections of the homosexual community like to play with (don't believe me?)
and therefore ideal for making films of that kind.
It's a shame he didn't make more past/far future fantasies like that instead of really daft films Red Dawn.
Don't get me wrong, Red Dawn is a guilty pleasure but imagine if Milius had made a film like Starship Troopers instead.
There are only so many uber masculine films that can knuckle crawl and swagger their way around the circuit (in the eighties you couldn't shift for them).
Arnie fitted that film and The Terminator because it was all about his body and he had the brain to work it in a way that the camera loved.
When he was re-marketed as Roger Moore with muscles he rarely approached that level of artistic success.