Has the idea of a dps penalty for attacking below your town hall level been discussed?  Something similar to the loot penalty for multiplayer attacks, just a percentage reduction of your army's damage when attacking a town hall lower than your own in war. 

As an example, if a town hall 10 attacks a town hall 9, his troops, spells, and heros do 10% less damage than if he were attacking a town hall 10 or 11.  The 10% is just a random number I threw in, it could be 3% or 30% or 13%, but the idea is the same, no matter the number. 

Also, it could be scaled up for dropping 2, 3, or more levels below your own. 

Problem is, it takes away the strategy of a lower base hitting up for a 2 star, thus allowing the bigger base to dip, and maximise your war score in a tight match up, or any match up in that case.