I agree with you, instance farm is against the spirit of Vanilla and IMO is a consequence of people refusing to agree with the game's demand of:
"If you want to reach max level, you need to play for months"
Its a huge demand from a game to a common person. People are not patient. Simple as that.
Im having tons of fun leveling in the world BUT while im playing i think to myself:
"There is no way other people will put up with this...im probably the only one enjoying this"
Thats what i think, but i could be wrong.