We’ve gotten closer now:
You can now do this by adding a tag.
Can also be covered by tags.
The Solved plugin. is great for this. Ideally it will also allow marking as solved without specifying a specific answer.
Don’t think we’ll ever have that natively, but how many ticketing systems (or companies) actually use this feature? I’ve worked professionally with two different ticketing systems (HelpScout and UserVoice) and time tracking was never a concern. It’s also something that’s easily left up to a separate program.
Some important “others”: Excellent search and automatic related-post suggestions to facilitate independent problem solving and fewer duplicate requests.
Also, and most importantly in my humble opinion, a ticketing system is the closest thing to a community for many companies. Starting off with Discourse as a ticketing system would be a great way to set yourself up for a more expansive community story as your company evolves.