In economy class, have seats designed so that reclining slides the seat bottom forward simultaneously. This might alleviate some of the recline wars, since it adds a cost to the passenger reclining and reduces the cost of the reclining on the passenger behind, rather than having all of the costs of reclining being forced onto the passenger behind.
I've used seats like this in SQ economy. It has these benefits, as well as feeling as if (I didn't measure) it reclines more than the typical economy seat. Don't know why everyone doesn't use them - does it weigh more? cost more? or is it just inertia on the part of most other airlines? In any case, there's nothing to design here; these seats exist and are in use.