Just remove loot penalty for collectors
This seems like a fairly obvious fix, for me: why not just remove the loot penalty for collectors? The loot penalty was intended to protect lower levels from being bullied by higher levels, but if a town hall 7 isn't bothering to move his collector loot into storages, there's no reason to protect that loot. Hell, SuperCell has said a couple of times they want to reward higher town halls, loot-wise, not punish them; give a loot BONUS for collectors for higher town halls. Instead of getting 50% from a town hall level below you, one could get 60%... and 70% for two town hall levels below, and so on. But seeing how, as a TH9, it takes no less skill for me to raid a town hall 7's collectors than another TH7 doing the same, I see no way in which the current loot penalty on collectors aligns with SuperCell's stated desires for high town halls' access to loot.