It would be good to be able to switch the view between miles and kilometres in each activity without having to go back to settings.
Sometimes I might be doing a 5k/10k run so want to see the overall distance (and splits) in km. Sometimes I will be doing a run of a particular number of miles or just want to see the distance in miles for a longer run.
I might still want to see pace in minutes per mile, but occasionally in minutes per km so it would be good to be able to change the view of that independently as well.