all the dev have to do is just take a look at FFXI and see what's been going during all these years of service and improve on it. open world HNMs are part of the world's lore, they are huge and should be so strong that it can't be easily camped and farmed regularly.

and from some of the respond here, the players are more worried about the sort of loots HNM would drop. just like the other thread about open world vs instanced content, if the player base sees that a certain content as a better way of getting better gear over the other, nobody will be bothered to do the other contents.

the good thing about FFXI and FFXIV is that stats from gears acts as a bonus and won't have too much of a impact to a player's ability to play what the game has to offer (unlike wow and swtor). unique loots from open world HNM at most would provide certain 'Enhance <ability>' traits or weapon/armor skins that players can't obtain elsewhere, such items are nice to have but won't break the game and provide bragging rights to egoist