First a little introduction as this is my first post here. I am using MapFactor Free navigation since recently and I really see a big potential in it as a mobile phone navigator. I am using Windows Phone 8.1 Lumia 920 and so far this is the closest thing that works to what I need. I also have a Navitel navigation but it has some drawbacks that I am not sure will get fixed.
So to the matter of hand. In my car I have an Alpine CDE-173BT receiver which is paired to my phone and upon ignition automatically makes a Bluetooth connection to my phone and automatically starts music stream from it. Usually I listen to music while driving and voices of navigation are being put on top of the music.. MapFactor GPS has nice audible voices which are heard even on top of the playing music, but still there can be a time when they are not heard clearly.
So it would be nice (if possible on WP 8.1, I guess android can handle this better) to have an option to mute/reduce volume of the other media playing at this time for the time of the instruction playback.. Nokia did this on Here Drive on WP 8.0 but changed it in WP 8.1 In 8.1 they made a phone call to the phone itself which would effectively pause everything else, then switch from A2DP to HFP bluetooth profile and play the instruction there... However there was a problem with certain amount of users (myself including) which car systems (both aftermarket and built-in) introduced a noticeable delay while switching the bluetooth profiles and picking-up the dummy call which resulted in just silence because the voice was being played back during this delay.. As you can guess Microsoft did not care to remedy this. Also for some reason pausing music while streaming through BT effectively mutes everything else, so just pausing/stopping the music is not much of an option.
So in short.. if possible muffle/mute any other media playback during voice navigation would be extremely useful feature. Any implications concerning the Windows Phone 8.1 platform which I met are stated above and would be good to take into consideration if such a feature is to be implemented some day.