Hilariously enough, this was just talked on about over at the EQ boards, but i'll be honest to say a few answers over there feel like a common staple that would be a general concept of what the two and how the two are differed from.
The item bolded is something I feel resonates heavily back over here, and where I feel the current situation stems from, especially with the usual posts of crying to "nerf content that requires some mental concepts of how to play the basic concept of this games mechanics." (i.e ShinEx, Rhabanastre, Amdapor Keep, back when it was one of the first few 50 dungeons we could do, etc..). As someone previously stated, this is an issue that must be resolved from both ends. Dev's need to stop catering to every single posts about crying to make content easier and take a firm stance to tell people to 'learn, contribute, and play'. And players need to learn that this game is not 'netflix fantasy' and it is an MMO that requires you to work together with other players and do what is expected of your class and of the game at the most basic of levels (dodge the pretty lights, stack with stack markers, place markers, do whatever visual or sound que that is given by the content which is more generous than other MMO's and its content out there, etc..), but because players have to go and do this, they want to cry that they have to move more than 2 feet and can't simply mash until it works, hence the 'silly demands' we see to 'nerf this or that.'Hardcore... learns to actually play the characters they play and utilizes all of the abilities the class has to offer. This doesn't just apply to their main, it applies to most of their alts as well. They will get good gear, good augs, max out all of the GOOD AA's for the class first and then just max out the AA's. Get all heroic AA's even though it's going back to old content.
Casuals... generally don't care about most of the above. As long as stuff dies, and things are enjoyable - all is well.
Note... neither is a negative. It's simply how the game is played by different people. The negativity comes into play with some people jump from EverQuest to Forum Quest and start making silly demands.
I'll be honest, I am still to this day wondering why SE even nerfed AK, the day I first saw the Bee's no longer spawning for burn i had a complete WTF moment and asked long and hard how was it even hard, when it was simple situational awareness and knowing the basics, be they obtained from learning the dungeon or just reading up on it somewhere.