This is an feature/impovement, but it was not possible to select it in the issue type.
The "server.properties" allows for setting a recommended resource-pack. However I would like to be able to set in an variable that selects the default resource-pack. Sure I could upload the resource-pack to somewhere and link to it but it seems kind of unnecessary for a player to download something they already have. So if it was possible to write "default" (or something).
Feature requests are not accepted on the bug tracker, as you discovered. The suggestions subreddit is the current place for posting feature requests.