Collector/Mine/Drill Bonus or Penalty Based Upon League
The problem I am addressing is the imbalance of loot available at different league levels. The general idea is that people tend to drop to gold or silver when they could easily be in a higher league.
How about giving a production bonus to collectors, mines, and drills based on league, starting at Crystal 3? For each league from there on up the collectors, mines, and drills would increase the production rate by 10%. I know that's a lot. However, currently production isn't really a considered valuable by most higher level players. This would make it worthwhile to remain in a higher league - plus it would make more loot available via the collectors, drills, and mines of other players within that league due to increased production. The league win bonus alone really doesn't offset the opportunities to be had by trophy dropping.
Right now now too much of the economy depends upon players abandoning the game while still producing resources. How about increasing resource production and availability for active players instead?
And of of course the counter measure is installing a similar penalty for TH9 players and above once they drop below Gold 3. That would curtail the loot available somewhat in the abandoned villages.