First, this is not a debate between casual and hardcore; there are plenty of threads about that. This topic is geared more towards what you want to see during your 1-50+ levels and also, what do you want to see as an endgame.

If you could create content of some sort, what would it be?

Perhaps you see the difficulty of an MMO as time put in. Maybe you feel, that since it is an MMO, being able to have many friends and do large scale content fits your idea of proper endgame content. Skill (however you measure it)? Regardless, what would you have us do? What type of content needs to be created for your play style?