It is true that you will not be able to see your child in his/her rear-facing car seat, but you will still be able to hear him/her. After a while you will realize that you are able to communicate with your child in the same way as before, even though the child is not able to see you. You can listen to the music or fairy tales, you can sing songs, your child can look at a book, etc.
If your child does get bored, it is very unlikely to do so because of facing rearward.
Looking back, while driving, to check on your child is very dangerous. If your child is seated in a rear-facing seat, you will probably not even try it. Therefore you will be more focused and attentive to the situation on the road.