Hi Eduardo,
Actually the aiming needs a bit of practice to get the feeling since at first you indeed often shoots through the ground on bumpy terrain

For the height visuals you have those slight visual lines but after a while it's more or less all about a feeling. For myself I only have rarely troubles with shooting through the ground.
The main issue users may encounter is when you shoot from a low elevation to someone placed on top of a hill like illustrated on this picture:

For that you'll have to aim at him directly (the higher the better, of course) instead of aiming at a spot behind him, what is often done on flat terrain. Those situations aren't happening too often and on such locations where the guys up the hill have a slight advantage it's better to maybe just start a flank from a more flat side or at least steady heightening.
I'm afraid to say that this "problem" you mentioned will probably not be updated. The bullet is moving straight to the crosshair location and if there's land between it, the bullet will stop as in real life, most likely.
We are listening very carefully to the feedback of our community, so I will discuss that with pasik to maybe have at least an option in the menu to make the height lines more visible if that would help. Maybe an other option would be to flatten a bit those bumpy heightenings. We'll let you know!
Jack
PS: does anyone else think that this is a big issue which should be updated?