The navigation should be on the remote.
Which is exactly what the iPad offers, using AirPlay, with my Airport Express connected to BeoSound 4/BL3s.
I'm using the iPod app on the iPad, with it on my office desk and can use it to control the music playing through the BS4, the volume, move between tracks, create a playlist and, if necessary, pick up the iPad and walk around with it or take it to another room. It's like your own Sonos. Of course, you could do the same thing with an iPhone, iPod Touch etc.
Which is why I asked why are B&O showing a Beosound Encore connected to BL3s and the Airport Express, being controlled via an iPhone? You could ditch the Encore and connect the Express directly to the BL3s and achieve exactly the same thing! The Encore in that example is superfluous :(
I want to buy the Encore, but I fear it's going to be a very expensive visual toy. I was told by my dealer it could be £2900.
It might be far cheaper to buy another BS4 or BS3200, both with a CD player (I still have CDs ;) and simply control them via the iPad/iPod/iPhone, as a remote!