I would suggest that Spotify on Sonos be extended. There is limited access to the great Spotify site on Sonos, and as you have to pay for Spotify Premium to access Spotify on Sonos, I feel that it would be fairer to have more of the usual Spotify info available.
As gprocess mentioned, there are already various ideas for a better Sonos app. Please use the search function and vote for them! If you don't find a specific idea, feel free to request that single feature in a new idea! Thanks 😉