C (Diadem) - Only one that is an actual problem content-wise IMO

L (More Quests) - Although I think we're fine with our current MSQ/Hidebrand/Scholar thing/event quest routine. More quests for the sake of having more quests is a waste of development resources, and should only be done if it expands the lore in a meaningful way. Alternatively, more varying dialogue depending on what classes you've leveled, or different quest objectives depending on player choices. Or hell, let us replay single player duties through the Unending Journey.

A (More Dungeons) - Although only if there's a real point to them. I -hated- the design of Arboretum and Pharos HM. Antitower and Amdapor HM though? I loved those two. Any more dungeons other than the standard two per patch should be tied to one of the sidequest chains/future Anima relic steps.