I agree of all what you say (except for the depth, the other have a reallt deep relationships for me either XD )
it's a grown up relationship... it's great in real life... but as I didn't reach any drama between those two, it's a bit boring to watch for a tv show (I mean their relationship, the show isn't boring at all)... I have a little stupid smile every time we saw them, but not that over squee, that heart beating I have when peter and Nathan are fighting for example... I need some drama to be happy XD and for the moment their relationship is too easy and simple (I know I have to go on, there will be drama later...)