I noticed that the door seemed smaller when He-Man cut through it, but that didn't mess the story up for me.
I think House of Shokoti I is an excellent story that really builds up suspense and gets the wheels of the narrative turning and hints that if this wasn't a children's show, the story could really get dark.
I also love "House of Shokoti II." In a lot of stories, the beast/monster/evil entity is scarier before you see it. Maybe that's why you prefer part I.
Of course, one reason I love this storyline is the key role the Sorceress plays.