With typical phone displays, when used in portrait (vertical) orientation, the map is taller than really needed, so it should be possible to give more space to the speed limit and current speed area at the bottom of the screen, which could probably be twice as big.
This would be very useful for owners of motorcycles with analogue speedo dials, especially if like me they find the numbers on the dial too small to read quickly.
Similarly in landscape (horizontal) mode, the map is wider than needed, but not really tall enough. In this case I would suggest that the information currently at the bottom of the screen should be displayed at the sides, in which case there should also be space to have bigger speed displays.
I currently use a separate GPS driven digital speed display, in addition to my Garmin satnav, but if it had a bigger speed display the MyRoute Navigation app could replace both devices.
Just to add to this - I would prefer to mount the phone horizontally on my motorcycle, it would be easier to mount and obscure less of my view, but I feel the current screen layout is not satisfactory in horizontal mode, so the suggestion to move the other information to the sides and make the map area taller would make horizontal mounting of the phone much more usable.