My daily mixes are mostly sorted by genre, but I thought there were artists that would fit the genre of some of my daily mixes very well that were missing. So, I think there should be an option on an artists page to add more songs by them in a specific daily mix.
Updated on 2019-09-04
Hello and thanks for bringing your feedback to the Idea Exchange.
A similar idea has also been suggested here: https://community.spotify.com/t5/Live-Ideas/Daily-Mix-Customization-Create-Remove-Add-Merge-Mixes/id...
We have also merged the votes from this idea to that original one. More information about how the Spotify Idea Exchange works can be found: here