Can we have a leaderboard system that shows people who have the most karma or the longest streak?
The interesting thing to note here is that we actually had a leaderboard system that showed people who accumulated the most karma in the past week.
The team decided to replace this system with what we have now because it was based exclusively on quantity, which as you know is not necessarily an indicator of quality.
Any system that is based on karma will favor the most active contributors in terms of the number of answers and the number of likes. The number of likes is usually a good indicator of quality, but the number of answers is not.
In other words, quantity will always beat quality if the system is based on karma.
This is why the team decided to find a way to celebrate the most active contributors without taking karma into account. The current system is based on activity days, not on the amount of karma someone accumulates in a given week.
Now, using streaks as a base for a leadership board was never really an option because of the way streaks work, i.e. you skip a day, you lose your streak.
This implies that the only way a contributor can move up the ladder is if someone else loses their streak. In other words, no matter what you do, you cannot be at the top of the list unless other people lose their streaks.
So who knows, maybe the leaderboard system will be changed again at some point. If or when that happens, the team will most likely consult the community on what they feel works in terms of leaderboards.