imbalance between wall price and effectiveness
Agree completely. It's a choice between either adjusting the weight of walls for what they are today (i.e. devaluated due to jump, quake and indirectly hound) or haha... rebalancing.
Rebalancing could be done in many ways, e.g. reducing wall prices to match their now reduced defensive value, rethinking the way they work (like slowing down troops going through earthquake debris or slightly electrocuting troops jumping over blue walls, just spitballing here...)