Grouping for XP is the only viable option. If you don't like it then you can solo or do other things which aren't efficient, but stop calling for them to destroy incentive (and thus the possibility) for a tried and proven way to level in an MMO which has lots of beneficial effects for the community/game.
I think that's a bit close minded to say "Grouping for XP is the only viable option.", it doesn't provoke much thought and produces a fallacy called a "false dichotomy". There are always other options.

Now I dont mean soloing is the alternate way of immersion in the game, what I mean is that group activities beyond grinding can be a lot more fun then just killing common monsters over and over