I agree, he was absolutely ghastly, both in appearance and deed (including mutilating a child with his demonic powers) in the story guest-starring Ghost Rider. I find it interesting that the more his appearance changed, the more his personality changed. When he started out, he simply had small fangs, bumps on his head, and pointed goblin ears (I remember him walking through a restaurant in a tux, wondering why everyone there was staring at him in horror).
As he become more demonic in appearance, with increasingly ridged skin, a long slippery tongue, and rows of long, razor-sharp teeth, he changed, becoming more cruel and predatory.
Then he started to think that he was some kind of agent of God on a mission, and then finally with the full Demogoblin personality coming into affect.
When the demon finally made itself known, this broke the mental and emotional continuity between the demon and Macendale's personality leading to a tongue of war between the two in their one body which only ended when the two physically split. Interestingly enough, the early Demogoblin manifested an ability where, if someone tried to punch him, their hands got burned with hellfire. This eventually was reduced to just a glowing aura, and then went away totally. The burning power was probably something to protect Demogoblin in his 'pupal' form while he was still developing his more sophisticated powers. If it had stayed however, this would have made him much more dangerous as attacking him directly would be close to impossible, especially for symbiote characters depending on what kind of fire surrounded him.
Honestly, I think the demon arc was the high point of the Macendale Hobgoblin, as he really became increasingly irreleventa until, ironically, his death in Hobgoblin Lives. I also very much curious to see what the new Demogoblin looks like, and if she (yes, the demonhost is a woman) will ever interact with Kingsley and/or Urich.