I don't get where that perception comes from that Cosmic Exploration is or was meant to be casual
crafter/gatherer content.
Crafter and gatherer content usually is considered more casual as the skill ceiling isn't as high. There are a lot of resources out there helping you to equip yourself optimally or assisting you in creating macros or finding the perfect rotations if you are doing it by hand. Same goes for gatherers with 960GP rotations for collectables etc.
TeamCraft is an excellent resource for all that kind of information.
All crafting missions from D-B aren't time limited either. One could argue that having the gathering missions on a timer is a bit too much.
A-missions are meant for Level 100 as it is clearly stated in-game. And I really did enjoy solving those recipes as some of them were tricky. Felt like a good puzzle
But as far as crafting and gathering content goes, Cosmic Exploration is 'midcore' to 'hardcore' crafter/gatherer content. Most expert recipes aren't the hardest we had but some actually require knowledge about crafting and CP management.