Oh man, Grimjack was one of my all-time favorite comics! That and Dreadstar were my two favs during that time. To me John Ostrander was and is one of comics' greatest writers, with his work on Grimjack and Suicide Squad.
But he did annoy me where Hawkworld was concerned. The ongoing title made such a mess of continuity! Why not say the story is taking place ten years in the past? Why does Katar Hol and Shayera have to arrive on Earth in present day? Ostrander spent so much time and effort in explaining who the Hawkmen of the JLA past and present were.
In fact, I would say Ostrander's Hawkworld led to the mess that became the whole Hawkman debacle. I don't know if he was to blame or if it was an editorial decision. :/