Thanks for the suggestion @L-Spijker-0
While on the route-planning end I would completely agree with you that TomTom is a hard requirement, we'll definitely not be including TomTom routing in our initial release (and honestly, likely all future releases) of the MRA Navigation Next application.
As @Steve-Lynch mentioned, we're using HERE as the basis for the premium sat-nav-esque "Navigation" part of "MRA Navigation Next".
That isn't to say that TomTom map layers won't be possible. For those that don't know: map-layers are the way the map looks, including things like labels and colours.