to me ive always been a person of exploration when im not leveling up, so i guess when i played WoW, that part was the most appealing. being able to jump and swim would allow me to climb mountains, swim to the bottom of lakes to gather materials for alchemy, and etc.
so then it would raise another point to removing the loading borders and make everything as part of one map. like the idea of Running from windurst scaling over the rocks and getting to tahrongi canyons, or even climbing up along the spine to get to a high part of the crags.

so yeah in the end i would have to give up the HD detail of the land, and maybe of the characters themselves. cause Andromeda brought up a good point about the character creations, if the detail is slightly dropped, customize the faces, and the body type as well. i always wanted to make a moderately fat character.