There only being enough exp to reach level 20 in the world means that if enemies give as much EXP as they do currently (without even exp increasing as you raise level) then there are only a few hours of combat in the entire game. So either something is up with beta level progression, something is up with the new content that makes us level a lot more slowly, or the game is *very* light on combat, because the EXP required to level barely increases per level.
I brought up that very same point earlier, that with three other maps, that's an average level spread of 3 levels per map, which seems extremely low.
But who knows, since the level cap is soft, the final level may end up being a lot closer to 30 (which could be a problem if the enemies top off at about level 20).