I know about the whole "Unsupported mobs don't behave as expected" thing, but i would like to know if someone could do anything about this. To sum it up, giants with items in their head/helmet slots will not display this item, unless it's a traditional helmet (Golden Helmet, Iron Helmet, etc.). You may not see any reason to fix this, but speaking as a person, who enjoys customizing the game with 3D models and commands a lot, giants could have been a wonderful way to make towering mobs, as they can easily be transformed into normal walking mobs by having a hostile mob ride them. I completely understand it if you're not going to do anything about this. I would also thank you a lot if you chose to actually fix it, as I've been waiting for the update where this would finally happen for a long time now.