If you have ever ridden the major climbs in France, you will know they have markers every kilometer on the way up. They ironically look like tombstones, but are yellow and white. They show you to name of the climb, the average gradient over the next km, altitude and distance to the summit. A small feature, but it would give riders an idea of how much farther the climb is and a little added detail overall.
I love those signs… It’s a little mental tick box to confirm that you are making progress. The only thing i don’t like is the top info. Letting you know the average gradient for the next km is horrid.
Zwift would need to make a decision on km or mile markers though. Although i ride in imperial i would vote for km’s as it just feels right.
Zwift would not have to make a decision on km vs mi. A good programmer can read your settings and make the correct markers.