I've just dealt with a user report complaining that their app will sometimes suddenly change the route as they're approaching a major junction, and in order to follow the new route would require a late and potentially dangerous change of lanes.

Given we now have lane guidance and lane count details available in the map data, it should be feasible to work out when it might be a really crazy idea to be telling the user to start following a different route to the one they're currently on, due to the need to make a sudden change of lanes, and stick to the existing route at least until the user gets past the current multi-lane section of their route and is in a better position to follow an alternative.

In a similar vein, even on sections of the route without lane details (whether because they just haven't been added yet, or because they don't need to be added), it'd also be preferable for the route recalculations not to assume that a user will be able to follow a different route through the next junction, if the junction would be reached within a minimum time threshold (to account for both the distance remaining and the speed at which their vehicle is travelling), and instead force any alternate route to still follow the same path through that junction, so that any change in route which IS then suggested gives the user enough time to see what the change entails.