I'm a casual player too, but I didn't mind at all giving up 4 hours every few days to do Dynamis. I don't know what kind of event they're going to implement to be limited time friendly... But I hope there are some long, mass participation events, too.
***Edit***
But I also don't want to see any
real endgame content until the level cap is where they're going to leave it, and the battle system is completely stable. So not for a solid year at least, along the same time frame as FFXI (See
this thread). They should work on quests and missions until then.