I've been a campaigner (well, not so publicly) for more player interaction in skyblock since I started playing and I think this is a great way to do so.
If you mean as in a leaderboard for different 'collections', so for example there would be a leaderboard for most carrots farmed, and for most creepers killed etc. I think it would be an amazing idea
Also, a leaderboard for the amount of coins on you, maybe even speedrun leaderboards directly implemented into the game rather than on external sources, although I am not sure how well that would or could work.
But overall I love the idea of some competition between players, however it may be implemented!