Attacking/defending at your own level
There's nothing worse than saving millions in coins and successfully defending against several attacks during the middle of the night (as that seems to always happen) and then out of no where a level 90+ comes in and takes everything because you're only a level 53 (blue levels) and they just decided to de-level to earn some extra loot. There needs to be a more level ground when attacking and defending. Perhaps I don't fully understand the "behind the scenes" of the matchmaking, but I think rating on your actual level - since that seems to be an accurate measure of where people are at in the game as far as time goes - rather than trophies is a much more fair approach. Maybe you could have matchmaking be based on intervals of 10 and everyone within 5 levels above and below (or more) your current level is an available opponent. Like I said, maybe this isn't the best idea (depending on how it's currently set up), but there has to be a more legit way to attack and defend against people that are in similar circumstances as you.