There are dozens of ways to level in this game; when you're level 30 it even equals out so that the previous level is obtained in the same amount of time as the last if you conduct similar activities.

I got to level 55 last beta without even trying.  All I did was explore, craft (resource gathering as a part of it) and do whatever event showed up.  I completely avoided all Heart Karma Points and still outleveled nearly everything I came across (luckily it brings you to an entertaining level).

There are many people who reciprocate the feelings of the OP; the opposition resound that said people simply do not understand the exploration experience.  There are no quest hubs, there is no efficient mob grinding, there is simply playing the game and leveling through sheer entertainment and the joy of finding and doing new things.

Massive experiences comes in from simply gathering resources (which are instanced so no one can take your node), crafting, PvP, exploration, dungeon completion, event completion, and even karma acquisition among many other things.  The fact that one is incapable of being beyond the necessary level is therefore purely brought on by their own inexperience with how the game runs itself (I.E. people are still treating the genre like it's WoW, and not how games such as UO were).

Perhaps it would be best to cater to those who have trouble focusing on something or those who don't have patience... though this game ultimately has completed what it set out to do; it is up to the player to figure out how to exploit the systems to their best experience and rise up in the ranks at an incredibly high rate.