Defense/Offense Weight limit tied to League level
My idea is to cap the Defense level and Offense level according to the league your are in. So on defense, if you are in a low league, you would have a cap on the hit points you can place in your active village. As you move up in league level this number would increase. If you decided to drop trophies, you would need to remove buildings/walls from your village to meet the weight limits of the lower league. Only the buildings placed in your active village are available for loot storage/production. On offense your army would be restricted to a max weight that would be derived from troops space, hit points, and DPS.
This would serve to push people into the appropriate league for their base level. You wouldn't be able to store large amounts of loot in lower leagues, because you would be short of collectors, storages, or defenses. But if you chose to be in a lower league, your attacking ability would be on par with everyone else so the little guys would not be completely crushed.
Another benefit would be a better variety of base designs and army compositions. Because you would have an overabundance of buildings and walls to choose from, the cost/benefit of placing each one on the map would become a new factor in base design. New army compositions would arise because each spot would need to be carefully considered for your raiding needs.
This idea could also be translated into the Clan Wars. Rather than ordering bases by TH level, bases would be ordered by Trophy level and the league restrictions would then apply to base design. This would create a more even playing field and offer the same benefits of base design variety. Attacking army limits would be tied to the defending base level, so a higher up would not gain an advantage by attacking low. Lower bases could still attack higher without restriction. This would bring a higher level of cooperation in clan wars and hopefully encourage more active clanmates.
I think this idea will bring back casual game play while encouraging more active players too. Please let me know what you guys think of this idea.