I dunno, I think I kinda associate 'hardcore' moreso with the time commitment aspect. I know players that, imo, are pretty terrible when it comes to combat (super slow to target, don't use combos cuz they don't wanna reposition, consider buffs 'optional', multiple wipes on low lvl content.. in a high lvl group) but some of these same players have all crafts at 50, decked out crafted gear (triple melds), a bajillion sidequests completed, almost maxed out GC seals w/ a ton of sets of GC gear, every useless seasonal event reward, and all those 'achievements' that are really nothing but a timesink.

I really don't think you can call them casual, or even semi-hardcore.. They can't tackle difficult battle content, but they've still played the hell out of this game (baring the bots ofc). The content they can't tackle makes up a very small percentage of the total content of XIV, and they've actually spent (or wasted..) more time playing XIV than most. I still think they're pretty hardcore.