I think it is already too late to suggest improvements for the next update. Whatever will be there is likely already at the final stages of testing.
But in general I am looking forward further improvements in such core features as offline maps, navigation, tracking of on-route waypoints, turn guidance, and elevation guidance. Every single of the above needs further improvements. I cold probably make a separate long post about each of these areas - what is lacking in each of these areas for me as a trail runner and how it can be improved.
My first priority would be to make trails more visible on the map when zooming out. In the current implementation trails become very thin, borderline invisible, at 0.5 km/mile zoom level and completely disappear at 1 km/mile zoom level. Suunto already has heatmap data. Perhaps Suunto could find a way to use that to determine which trails are more popular and should be prioritized on the map when the map is zoomed out.
Perhaps the second priority would be to make elevation data more accurate. When I plan routes in Suunto App, the total elevation gain is routinely up to 20% under of what is actually measured by the watch when I complete the route. That is especially bad on a rolling hills terrain, but even in big mountains with large climbs, elevation gain is almost always at least 10% less than actual. That also affects climb guidance for individual climbs because it is based on the same flawed low accuracy data.
Also, it would be really awesome to enable Suunto App to store maps offline and to allow making a new route and transfer to the watch while in activity in wilderness without having data on the phone. That would be a powerful feature that would, to a large degree, alleviate inability to route on the watch. It should already be possible to transfer new routes to the watch on the fly, but that currently requires having mobile data on the phone, which makes it much less useful for many of us.