I'm getting a real Kirby vibe from this one. Did he ever draw Him/Adam
Warlock?

Al-

Kirby drew Him in FF #66-67 and Thor #163-166.

Had he remained the enigmatic Him, he might have -- but Adam Warlock
didn't do much for me.

Other than being enigmatic, what reasons was Him more appealing than Adam Warlock?

I read in a Jack Kirby Collector that the character "Him" was in some ways linked to Kirby's interpretation of Objectivist ideals, and that Stan Lee rewrote the issue so heavily it basically flipped the point of view in the plot. Also that this event was one of the crucial events in making Kirby disillusioned with his collaboration with Stan Lee.

Seems so weird to me. I can understand objectivism being a point of contention for Lee and Ditko, but the idea that it was also part of the conflict between Lee and Kirby just seems strange. Kirby was, after all, far from an objectivist himself.

The opening comments in Thor Marvel Masterwork #8 talk about Kirby's challenges and frustrations at Marvel and how that affected his work on the issues within volume #8.  The origin of Galactus story was not continuous, but broken up with other issues in between.  In fact, the bonus original art in the back indicates that Thor and Galactus were going to team-up for some reason.  But this never happened in the finished product.  Also there is some speculation that Him (aka Warlock) was a prototype for some of Kirby's eventual work on the New Gods over at DC.

All that to say, that the "warrior madness" that comes upon Thor in Marvel Masterwork #8 is directed at Him because Him ran off with Sif.  The story only runs two issues (with hints in the previous two issues).  I get the impression that Kirby had more to say about Him, but never did, for whatever reason.