I suppose you are not completely aware of the difference between
view angles and body angles. The view angles can be seen as the angles of the head, while the body angles can be seen as the angles of the rest of the body.
When a player looks upwards at let's say +45 degrees, his body should bend back about 15 degrees. Since this value is function of the head's angles, we found that
body angles pitch = - view angles pitch / 3
was a good value. I don't think your problem with the bots aiming at the ground is related to this fact in any way. I would rather look at the waypoint navigation.