I’m riding Zwift since 3 weeks now an I love it. Great fun.
As I use a gaming laptop as the client machine the graphics are a litte like in the mid-2000s. This could be better I can imagine. With the wide support of Devices runing from phones to real PCs i can understand that the graphics should be fine for alle devices and big textures are not good for this.
So: Why not provide a HD texture package for Windows clients? Like the ones for Fallout 4 for example. So everyone with a proper machine can choose to install them.
From the dev side I can imagine that the team is currently improving the network and serverside to handle all the new Zwifters properly and to keep the system running as smooth as it did. And this should be the main task.