While I agree that the level cap is very low, I didn't really pay attention to it. Levels are not something you work towards in this game. Once you reach the required levels to unlock the skills, leveling up becomes irrelevant. As long as you play the game, you are guaranteed to get there, most likely before you complete 50% of the game. When I got my level 30 notification, it got me by surprise because I didn't remember when I got the previous level notifications...
I agree with the OP, it's too low. I'm around half way through too, but have hit the level cap.
I am less concerned about the level itself, just the fact that once you hit the cap, XP isn't displayed on the screen, and therefore you cannot tell whether you've managed a head-shot when long range sniping.
Before the level cap you get an XP boost displayed confirming the head-shot, that's gone now.