I just started using this service and it seems great, yet I am missing a couple of things.
1. Be able to modify paper.yml, spigot.yml, bukkit.yml
2. We can only modify server.properties to a certain extent, such as motd, players, etc. I am missing stuff like the SHA1 entry for the resource pack.
3. I know we can not upload nor download files, but it would be nice to either allow uploading of .yml and .json configuration files (because now it's open file, paste your config and save).
3.1. The ability to upload .db files for plugins that use them such as luckperms.
If 3.1. isn't a possibility, I've seen that most plugins support mysql for database storage. It would be nice if mysql could be integrated here to make use of it.