I'd argue that the way many people think about casual content is wrong. It really looks like "casual content" is self-completing content to you guys. Content you can join and clear without knowing a thing about the game or your job and without being accountable for you actions since you can just be carried by the rest of the party/alliance. That's the case for dungeons and most of the 24 man raids.
I'd say casual content is content that can be cleared reasonably fast with some practice by a group of coordinated people without serious physical or mental disabilities.
Now, clearly difficulty is subjective. Some people don't understand crafting rotations and find them difficult, but I think no one in their right mind would then proceed to define crafting as "hardcore content". But at the very least, extreme trials and the first 2-3 turns of savage can hardly be defined hardcore content. They just require you to...play and think, I guess? But I do realized that when the rest of the game can be completed with zero effort, even that may look like an ordeal.
Personally, I would define ex trials and the first turn of a savage tier as very casual friendly.
