Pretty sure it's possible to have both if worked out right,
And for HNM was thinking... although in FFXIV I would be one of those that may never get to do them with current life style, Not sure but how about it's open world content but as soon as you/your party claim then it changes the field into instanced field ?? like say for FFXI you claim Fafnir and it shows big message FAFNIR CLAIMED! on each party members screen (if you win the pull) while in instance mode others can watch but cannot cure or do anything, unless the party requests for help. would be nice if these type of NM's or special mobs have their own/special battle music too + after going into instance the environment can change. Like say one type of dragon NM uses thunder move then weather changes to lightning storm while battling.
I dunno if I'm making any sense lol.