For our poll, The winner by a slight margin was update rankings weekly (50%), closely followed by "as soon as possible" (40%). I've been thinking about when I have time to reliably update things and realized what I think is the perfect schedule to give people to rely on.
We might all be in different timezones, but we all know when daily reset is. When new cards comes out is about a weekly cadence. Putting that together, what makes the most sense to me is to update the ranking just after the reset, every time new cards are added. This gives everyone 24 hours to get the new card up.
So most weeks I'll do one update, plus an extra update for weeks with a new mythics or new cities. We don't need a new update for "I'm sorry" epics or new guild war troops since it's not possible to get those to mythic immediately.
Does that sound fair guys? So after the next reset, I'll update the thresholds and rankings.