That is a nice image! I too think it will probably be a UI like that.
Perhaps these multipliers need to be tested in practice, if the values are too high or too low they need to be adjusted.
It might be possible to develop an add-on that converts leaderboard scores into medals for betting on them and battles with them (I received a request for a game like slot machine), but perhaps such a medal feature would be a separate add-on.
I think an idea I have at the moment is the ability to link with other add-ons. e.g. if pokemonki and pokemon groups were linked users would be able to trade and battle for pokemon (or collaborate with Ankimon), but most leaderboard users should not be interested in pokeman (maybe) so it is reasonable to separate such a feature from the leaderboard. (and it is easier to develop add-ons separately than to integrate them.)
I received a similar request for the add-on Anki Kill Streaks (e.g. to record the coins collected and score them). In these cases I could develop separate servers for each but connecting to the leaderboard would allow users to register only once and make it easier for me to manage and enhance the server.