When in the data explorer, I can still see my old or mistakenly created leaderboards there. It'd be nice if we could drop them so we can keep a clean workspace.

I have to add, when creating partitioned leaderboards, if you set them up incorrectly, they make such a mess that you can't get rid of. It becomes very hard to develop interesting leaderboards and debug them.

My current workflow is

1. Save my project snapshot before adding leaderboards.
2. Copy that snapshot over to a new project.
3. Experiment on the leaderboards there.
4. Once you have things working, copy the additions back to the source by hand (Expect mistake to be made in this dev project you don't want to copy over via snapshot)

I also encounter this problem. It's so frustrating. 

Please fix it as soon as possible. Thanks